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Parpa K, Manning JT, Kobus M, Mason L, Michaelides M. The associations between digit ratio (2D:4D and right - left 2D:4D), maximal oxygen consumption and ventilatory thresholds in professional male football players. Am J Hum Biol 2024; 36:e24047. [PMID: 38308173 DOI: 10.1002/ajhb.24047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 01/21/2024] [Accepted: 01/22/2024] [Indexed: 02/04/2024] Open
Abstract
INTRODUCTION Digit ratio (2D:4D: the relative length of the 2nd and 4th digit) is thought to be a negative correlate of prenatal testosterone. The 2D:4D is related to oxygen metabolism, but the precise nature of this relationship is unclear. The purpose of the present study was to consider associations between digit ratios (right 2D:4D, left 2D:4D, right-left 2D:4D [Dr-l]) and VO2max and ventilatory thresholds (VT1 and VT2). METHODS One hundred and thirty-three Caucasian (n = 133) professional football players competing in Cyprus participated in the study. Players underwent anthropometric measurements, and digit lengths were measured from hand scans. They also completed an incremental cardiopulmonary test to exhaustion on a treadmill. RESULTS There were negative correlations between digit ratios and VO2max (right 2D:4D, r = -.65; left 2D:4D r = -.37, both p < .0001; Dr-l r = -.30, p = .0005). There were no relationships between digit ratios and VT1. For VT2, there were negative relationships with digit ratios (right 2D:4D, r = -.43, p < .0001; left 2D:4D, r = -.21 and Dr-l, r = -.21, both p = .02). Digit ratios are negatively related to VO2max with large (right 2D:4D) and medium (left 2D:4D, Dr-l) effect sizes. For VT2, there were also negative correlations, which were medium (right 2D:4D) and small (left 2D:4D, Dr-l). CONCLUSION Our findings may help clarify the relationships between digit ratios and high-intensity actions for extended periods, which are dependent on efficient oxygen metabolism.
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Affiliation(s)
- Koulla Parpa
- School of Sciences, University of Central Lancashire - Cyprus Campus, Larnaka, Cyprus
| | - John T Manning
- School of Sport and Exercise Sciences, Applied Sports, Technology, Exercise, and Medicine (A-STEM), Swansea University, Swansea, UK
| | - Magdalena Kobus
- Department of Anthropology, Faculty of Biology and Environmental Protection, University of Lodz, Poland
- Institute of Biological Sciences, Faculty of Biology and Environmental Sciences, Cardinal Stefan Wyszynski University in Warsaw, Warsaw, Poland
| | - Laura Mason
- School of Sport and Exercise Sciences, Applied Sports, Technology, Exercise, and Medicine (A-STEM), Swansea University, Swansea, UK
| | - Marcos Michaelides
- School of Sciences, University of Central Lancashire - Cyprus Campus, Larnaka, Cyprus
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Hashemian SS, Golshani S, Firoozabadi K, Firoozabadi A, Fichter C, Dürsteler KM, Brühl AB, Khazaie H, Brand S. 2D:4D-ratios among individuals with amphetamine use disorder, antisocial personality disorder and with both amphetamine use disorder and antisocial personality disorder. J Psychiatr Res 2024; 170:81-89. [PMID: 38113678 DOI: 10.1016/j.jpsychires.2023.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/01/2023] [Accepted: 12/06/2023] [Indexed: 12/21/2023]
Abstract
BACKGROUND There is sufficient evidence that the index-finger-to-ring-finger-ratio (2D:4D-ratio) is associated with testosterone and estrogen exposure during the fetal stage. More specifically, a lower 2D:4D-ratio (that is; a shorter index finger, compared to a longer ring finger) was associated with a prenatally higher testosterone and lower estrogen exposure during the first trimester of the fetal stage. At a behavioral level, among adults, a lower 2D:4D-ratio was associated with a higher competitive performance among both female and male professional athletes, and with personality traits such as higher scores for mental toughness, dark triad traits, and aggressive behavior, and internet use disorder. Here, we tested, if 2D:4D-ratios differed among three clinical samples of individuals with amphetamine use disorder (AUD), antisocial personality disorder (ASPD), or both AUD and ASPD (AUD + ASPD), and when compared to healthy controls. METHOD The sample consisted of 44 individuals (mean age: 32.95 years; 22.7% females) diagnosed either with AUD (n = 25), ASPD (n = 10) or both AUD + ASPD (n = 9), and of 36 healthy controls (mean age: 23.28; 25% females). After a thorough clinical assessment, participants provided the scans of their right-hand palm to measure the lengths of their index finger and ring finger. Further, participants with AUD, ASPD and both AUD + ASPD completed a series of self-rating questionnaires on Dark Triad traits, narcissism sensitivity, and intolerance of uncertainty. RESULTS Compared to healthy controls, participants with AUD, ASPD, or AUD + ASPD showed statistically significantly lower 2D:4D-ratios. Participants with AUD + ASPD showed statistically significantly lowest 2D:4D-ratios, compared to participants with AUD and compared to healthy controls. For the clinical sample, a lower 2D:4D-ratio was associated with higher Dark Triad traits. 2D:4D-ratios were unrelated to narcissism sensitivity or intolerance of uncertainty. Higher scores for Dark Triad traits were associated with higher scores for narcissism sensitivity and intolerance of uncertainty. CONCLUSIONS Compared to healthy controls, individuals with amphetamine use disorder and concomitant antisocial personality disorder (AUD + ASPD) appeared to have been exposed to particularly high prenatal testosterone and particularly low estrogen concentrations, which, at a behavioral level, might have led to a fast life history for immediate resource acquisition.
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Affiliation(s)
- Seyed Sepehr Hashemian
- Centre de Recherche Charles-Le Moyne, Longueuil, Québec, Canada; Faculty of Medicine and Health Sciences, Université de Sherbrooke, Longueuil, Québec, Canada
| | | | - Kimia Firoozabadi
- Faculty of Medical Sciences, UCL Medical School, University College London, London, WC1E 6BT, UK
| | - Ali Firoozabadi
- Research Center for Psychiatry and Behavioral Sciences, Department of Psychiatry, Hafez Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Christian Fichter
- Department of Psychology, Kalaidos Private University of Applied Sciences, Zurich, Switzerland
| | - Kenneth M Dürsteler
- Psychiatric Clinics, Division of Substance Use Disorders, University of Basel, 4002, Basel, Switzerland; Center for Addictive Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, 8001, Zurich, Switzerland
| | - Annette B Brühl
- Center for Affective, Stress and Sleep Disorders (ZASS), Psychiatric University Hospital Basel, 4002, Basel, Switzerland
| | - Habibolah Khazaie
- Sleep Disorders Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Serge Brand
- Kermanshah University of Medical Sciences, Kermanshah, Iran; Center for Affective, Stress and Sleep Disorders (ZASS), Psychiatric University Hospital Basel, 4002, Basel, Switzerland; Sleep Disorders Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran; Department of Sport, Exercise and Health, Division of Sport Science and Psychosocial Health, University of Basel, Basel, Switzerland; School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Center for Disaster Psychiatry and Disaster Psychology, Psychiatric University Hospital Basel, Basel, Switzerland; Center of Competence for Military and Disaster Medicine of the Swiss Armed Forces, Switzerland.
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Ribeiro E, Neave N, Marsili BK, Figueiredo ECG, Martino-Andrade AJ, de Moraes RN. Prenatal androgenization (2D:4D) predictions of tennis match-play success in junior players: A search for physiological explanations. Am J Hum Biol 2024; 36:e23979. [PMID: 37602536 DOI: 10.1002/ajhb.23979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 08/01/2023] [Accepted: 08/04/2023] [Indexed: 08/22/2023] Open
Abstract
AIM This study aims to investigate the possible association between digit ratio (2D:4D) and match-play success (MPS) in junior tennis players. In addition, we consider the possible explanatory pathways of these associations in relation to psychological, strength, power, and hormonal parameters. METHODS We performed a cross-sectional study, with a sample comprised of 64 male junior tennis players (11-18 years old). Digit ratio was calculated from direct finger measurements. In addition, we measured the ratio of wins by number of matches played in 5 years of official competition (MPS), handgrip strength (HGS), standing long jump (SLJ), training (in weekly hours), and expertise (number of years in official competition). Salivary testosterone and cortisol levels were measured before and after physical "challenge" tests. RESULTS The 2D:4D correlated negatively with HGS and SLJ. MPS was also negatively associated with 2D:4D, but was positively correlated to HGS, expertise, training, and self-confidence (SC). Multiple linear regression showed 2D:4D and expertise were associated with MPS (43%-54%). None of the physical, or hormonal variables tested explained the links between 2D:4D and MPS. CONCLUSION Therefore, the specific fitness components influenced by prenatal androgenization that moderate sports success remain unknown. Future studies should explore the interaction of 2D:4D, with tennis exercises as a challenge to induce hormonal change, the effect of pubertal stage, and the influence of aerobic endurance in determining MPS.
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Affiliation(s)
- Evaldo Ribeiro
- Litoral Sector, Federal University of Paraná, Matinhos, Brazil
- Department of Physiology, Federal University of Paraná, Curitiba, Brazil
| | - Nick Neave
- Department of Psychology, Northumbria University, Newcastle-upon-Tyne, UK
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Aslan Genç H, Özcan Morey A. Lower digit length ratio and aggression in adolescents and young adults with boxer's fracture: A case-control study. Aggress Behav 2023; 49:679-686. [PMID: 37467363 DOI: 10.1002/ab.22106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 07/09/2023] [Accepted: 07/12/2023] [Indexed: 07/21/2023]
Abstract
Recent evidence shows that a lower second-to-fourth digit ratio (2D:4D), which is a sexually dimorphic trait and the indicator of prenatal testosterone exposure, may be associated with aggressive behaviors. In this cross-sectional, case-control study, we investigated: (1) Are the aggression and impulsivity levels and emotional problems higher? (2) Is the 2D:4D ratio lower in adolescents and young adults who presented with a fifth metacarpal neck fracture (boxer's fracture) compared to controls? (3) Is the digit ratio correlated with aggressive measures in individuals with a fifth metacarpal neck fracture? Seventy-one consecutive patients presented with a fifth metacarpal neck fracture within the age range of 11-25 years old comprised the study group. The control group consisted of 71 age and sex-matched subjects without a history of aggression-related injury. The aggression, impulsiveness, and psychosocial well-being were measured by self-reported questionnaires. 2D:4D was measured by conventional radiography. The 2D:4D ratio was similar between groups, however, when the analyses were conducted separately for sex, females in the study group showed lower 2D:4D than females in the control group (p = 0.001). The aggression level of the study group, measured by the Buss-Perry Aggression Questionnaire was higher than the control group (p = 0.014). The impulsiveness scores on the Barratt Impulsiveness Scale-11 were similar (p = 0.60) and the total difficulty score on the Strengths and Difficulties Questionnaire was higher in the study group (p = 0.009). A lower 2D:4D ratio significantly predicted verbal and total aggression scores (p = 0.036, p = 0.032, respectively). Our findings suggest that females with a history of aggression-related injury have lower 2D:4D, and a lower 2D:4D is correlated with higher aggression levels in both sexes. Understanding and addressing aggression in these patients may help prevent further self-inflicted injuries.
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Affiliation(s)
- Herdem Aslan Genç
- Department of Psychiatry, Koç University School of Medicine, Istanbul, Turkey
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Nobari H, Eken Ö, Prieto-González P, Oliveira R, Brito JP. Association between 2D:4D ratios and sprinting, change of direction ability, aerobic fitness, and cumulative workloads in elite youth soccer players. BMC Sports Sci Med Rehabil 2023; 15:45. [PMID: 36978178 PMCID: PMC10045863 DOI: 10.1186/s13102-023-00654-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 03/21/2023] [Indexed: 03/30/2023]
Abstract
BACKGROUND The aim of this study was two-fold: (i) to determine the correlation between 2D:4D, maximal oxygen uptake (VO2max), body fat percentage (BF%), maximum heart rate (HRmax), change of direction (COD), and accumulated acute and chronic workload variables; (ii) to verify if the length of the second digit divided by fourth digit (2D:4D) can explain fitness variables and accumulated training load. METHODS Twenty elite young football players (age: 13.26 ± 0.19 years; height: 165.8 ± 11.67 cm; body mass: 50.70 ± 7.56 kg; VO2max, 48.22 ± 2.29 ml.kg- 1.min- 1) participated in the present study. Anthropometric and body composition variables (e.g., height, body mass, sitting height, age, BF%, body mass index, right and left finger 2D:4D ratios) were measured. The following fitness tests were also conducted: 30 - 15 Intermittent Fitness Test (VO2max and HRmax), COD (5-0-5 agility test), and speed (10-30msprint test. HRmax and the training load were also measured and monitored using the Rate of Perceived Exertion during the 26 weeks. RESULTS There were associations between HRmax and VO2max, between 2D and 4D lengths and Left and Right hand ratios. Also, in AW with Right and Left 4D. The CW and de ACWR with the Right 4D. There were other associations between physical test variables and workload variables. CONCLUSIONS Under-14 soccer players with low right and left-hand 2D:4D ratios did not perform better in the selected fitness tests to assess VO2max, COD, or sprint ability. However, it cannot be ruled out that the absence of statistically significant results may be related to the small sample size and the maturational heterogeneity of the participants.
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Affiliation(s)
- Hadi Nobari
- Department of Exercise Physiology, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, 56199-11367, Iran.
- Faculty of Sport Sciences, University of Extremadura, Cáceres, 10003, Spain.
| | - Özgür Eken
- Department of Physical Education and Sport Teaching, Inonu University, Malatya, Turkey
| | - Pablo Prieto-González
- Health and Physical Education Department, Prince Sultan University, Riyadh, 11586, Saudi Arabia
| | - Rafael Oliveira
- Sports Science School of Rio Maior-Polytechnic Institute of Santarém, Rio Maior, 2040-413, Portugal
- Research Center in Sport Sciences, Health Sciences and Human Development, Vila Real, 5001-801, Portugal
- Life Quality Research Centre, Rio Maior, 2040-413, Portugal
| | - João Paulo Brito
- Sports Science School of Rio Maior-Polytechnic Institute of Santarém, Rio Maior, 2040-413, Portugal
- Research Center in Sport Sciences, Health Sciences and Human Development, Vila Real, 5001-801, Portugal
- Life Quality Research Centre, Rio Maior, 2040-413, Portugal
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The effects of sex, nation, ethnicity, age and self-reported pubertal development on participant-measured right-left 2D:4D (Dr-l) in the BBC internet study. J Biosoc Sci 2023; 55:383-395. [PMID: 35088686 DOI: 10.1017/s0021932022000049] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Digit ratio (2D:4D) - a proxy for prenatal sex steroids - shows sex, nationality and ethnic differences and is linked to pubertal onset. It is unclear whether right-left 2D:4D (Dr-l) also correlates with prenatal sex steroids, as evidence of these differences has been less conclusive. The present study examined the effects of sex, nation, ethnicity, age and self-reported pubertal development (i.e. the rate of physical development and age at menarche [females] or first shave [males]) on Dr-l in a large online study (the BBC internet study). Digit lengths were self-measured in 201,865 adults (110,955 males) and the sample of nations included 41 countries. Participants reported the self-perceived rate of physical pubertal development on a five-point scale (from very slow to very fast) and provided information on the age at menarche or first shave. Adult (>17 years) males had lower Dr-l than females with weak effect size across 41 nations (males-females; d = -.065, p < .0001). There were sex and ethnicity effects on Dr-l across seven ethnic groups with males < females and lower Dr-l in Whites and Middle/Near Eastern participants compared to Asian, Black and Chinese respondents. Considering age effects, the authors focused on participants >12 years; there were stable sex differences and a weak positive effect of age on Dr-l. Dr-l showed a positive relationship with the rate of physical development and a negative relationship with age at menarche or first shave. Relationships were present in males and females with stronger effects in the latter. It is concluded that Dr-l shows a weak sex difference (males < females) independent of nation, ethnicity and age, and suggest that Dr-l is a proxy for prenatal sex steroids.
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Does maturity estimation, 2D:4D and training load measures explain physical fitness changes of youth football players? BMC Pediatr 2022; 22:726. [PMID: 36539728 PMCID: PMC9764734 DOI: 10.1186/s12887-022-03801-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVES The purpose of the present study was two-fold: (1) To analyse physical fitness changes of youth football players after a full-season; and (2) to examine whether physical fitness changes are explainable by estimated maturity status, 2digit:4digit ratio (2D:4D) from each hand and training load (TL) measures. METHODS Twenty-seven youth elite Under-15 football players were daily monitored for training load measures during 38 weeks. At the beginning and at the end of the season, all players were assessed for physical fitness. Also, the maturity status estimation and the length of the second and fourth digits of both hands were collected at the beginning of the season. RESULTS Significant differences were found for all physical fitness measures after the season. The second and fourth digits of left and right hands had negative moderate correlations with change of direction (COD) changes (r=-.39 to - 0.45 | p = .05 to 0.02). Also, the maturity offset measure had negative moderate correlations with COD changes (r=-.40 | p = .04). From the reported significant correlations, the maturity offset, Left 4D, Right 2D and Right 4D significantly predicted the Mod.505 COD test changes (β = 0.41, p = .04; β = -0.41, p = .04; β = -0.45, p = .02; and β = -0.44, p = .03, respectively). CONCLUSION The maturity offset and the 2D:4D measures have the potential to predict COD performance changes over-time in youth football players. Given the lack of associations between the maturity estimation, 2D:4D and training load measures, with the overall physical fitness measures, coaches should rely only at COD changes.
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Hirschberg AL. Female Hyperandrogenism in Elite Sports and the Athletic Triad. Semin Reprod Med 2021; 40:32-41. [PMID: 34634825 DOI: 10.1055/s-0041-1736337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Essential hyperandrogenism seems to be overrepresented in female elite athletes. This applies to mild forms such as polycystic ovary syndrome, as well as rare differences/disorders of sex development (DSD). The reason is likely a selection bias since there is increasing evidence that androgens are beneficial for athletic performance by potent anabolic effects on muscle mass and bone mass, and stimulation of erythropoiesis. XY DSD may cause a greatly increased production of testosterone in the male range, that is, 10 to 20 times higher than the normal female range. The established regulations concerning the eligibility of female athletes with severe hyperandrogenism to compete in the female classification remain controversial. The most common cause of menstrual disorders in female athletes, however, is probably an acquired functional hypothalamic disturbance due to energy deficiency in relation to energy expenditure, which could lead to low bone mineral density and increased risk of injury. This condition is particularly common in endurance and esthetic sports, where a lean body composition is considered an advantage for physical performance. It is important to carefully evaluate endocrine disturbances and menstrual disorders in athletes since the management should be specific according to the underlying cause.
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Affiliation(s)
- Angelica Lindén Hirschberg
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.,Department of Gynecology and Reproductive Medicine, Karolinska University Hospital, Stockholm, Sweden
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Nobari H, Alves AR, Clemente FM, Pérez-Gómez J. Influence of 2D:4D ratio on fitness parameters and accumulated training load in elite youth soccer players. BMC Sports Sci Med Rehabil 2021; 13:125. [PMID: 34635156 PMCID: PMC8504125 DOI: 10.1186/s13102-021-00354-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 09/28/2021] [Indexed: 11/10/2022]
Abstract
BACKGROUND Digit ratio (2D:4D) characterized by the length of the second digit (2D) divided by the length of the fourth digit (4D), is a powerful marker of athletic performance. Some studies showed a negative correlation between 2D:4D ratio and sports performances. OBJECTIVES The purpose of the present study was three-fold: (1) to analyze the influence of anthropometric and 2D:4D ratio on variations of accumulated training load (ATL) and fitness parameters: maximal oxygen uptake (V̇O2max), countermovement jump (CMJ), isometric muscular strength of the knee extensor for hamstring (ISH) and flexor for quadriceps (ISQ) muscles; along three stages of evaluation of soccer players based on playing positions; (2) to analyze the correlations between 2D:4D ratio and aforementioned parameters; and (3) to investigate if variance in fitness levels and ATL can explain the 2D:4D ratio. METHODS Twenty-four elite players under 17 years were daily monitored for their rating perceived exertion and ATL across 24 weeks over the season. Soccer players have also measured in three stages for anthropometric traits and fitness parameters. RESULTS Significant differences were observed between playing positions for body mass, goalkeepers had higher body mass compared to centre-midfielder and winger players. Moreover, there were significant differences in ATL between early-season to mid-season in goalkeepers (P = 0.032). The 2D:4D ratio (left and right) shown largely and negatively association with muscular strength (ISQ: r = - 0.80; r = - 0.78, P ≤ 0.001, ISH: r = - 0.63; r = - 0.62, P = 0.001, respectively) and VO2max changes (r = - 0.55, P = 0.005; r = - 0.50, P = 0.013, respectively); lastly, both 2D:4D ratio significantly predicted changes in muscular strength and VO2max in young soccer players. CONCLUSIONS Goalkeepers tended to have higher body mass compared to centre-midfielder and winger players; and 2D:4D ratio revealed a mighty predictor of physical fitness changes in soccer players. Evidence should be helpful to professionals to highlight the usefulness of the 2D:4D into the identification of talent, but also to optimize young players' performance.
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Affiliation(s)
- Hadi Nobari
- Department of Exercise Physiology, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, 56199-11367, Ardabil, Iran. .,Sports Scientist, Sepahan Football Club, 81887-78473, Isfahan, Iran.
| | - Ana Ruivo Alves
- Department of Arts, Humanities and Sport, Polytechnic Institute of Beja, 7800-295, Beja, Portugal.,Research Center in Sport Sciences, Health Sciences and Human Development, CIDESD, 5001-801, Vila Real, Portugal
| | - Filipe Manuel Clemente
- Escola Superior Desporto e Lazer, Instituto Politécnico de Viana do Castelo, Rua Escola Industrial Comercial de Nun'Álvares, 4900-347, Viana do Castelo, Portugal.,Instituto de Telecomunicações, Delegação da Covilhã, 1049-001, Lisboa, Portugal
| | - Jorge Pérez-Gómez
- HEME Research Group, Faculty of Sport Sciences, University of Extremadura, 10003, Cáceres, Spain
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Pasanen BE, Tomkinson JM, Dufner TJ, Park CW, Fitzgerald JS, Tomkinson GR. The relationship between digit ratio (2D:4D) and muscular fitness: A systematic review and meta-analysis. Am J Hum Biol 2021; 34:e23657. [PMID: 34331730 DOI: 10.1002/ajhb.23657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/18/2021] [Accepted: 07/20/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Digit ratio (2D:4D), a marker of prenatal testosterone exposure, is a weak negative correlate of sports/athletic/fitness performance. While numerous studies have examined the relationship between 2D:4D and physical fitness, there has never been a comprehensive study that has synthesized studies examining relationships between 2D:4D and muscular fitness. OBJECTIVES To systematically review and meta-analyze the relationship between 2D:4D and muscular fitness measured as handgrip strength (HGS). METHODS We systematically searched five electronic databases, reference lists, topical systematic reviews/meta-analyses, and personal libraries in November 2020. Peer-reviewed, cross-sectional studies that reported Pearson's correlation coefficients between objectively measured 2D:4D and HGS were included. We used random-effects meta-analysis to estimate the pooled correlation and the 95% confidence interval (95%CI), and moderator analyses to estimate the influence of sex and age. RESULTS Data from 22 studies, representing 5271 individuals from 11 countries ranging in (mean) age from 10.4 to 58.0 years, were included. Overall, there was a weak negative correlation between 2D:4D and HGS (r = -0.15, 95%CI = -0.20 to -0.09), indicating that individuals with low 2D:4Ds had high HGS. We found substantial heterogeneity between studies (Q = 123.4, p < .0001; I2 = 74%), but neither sex (Q = 0.003, p = .96) nor age (Q = 0.46, p = .50) significantly moderated the pooled correlation. CONCLUSIONS We found a weak negative relationship between 2D:4D and HGS, which showed substantial heterogeneity between studies, but was neither moderated by sex nor age. Our finding probably reflects both the long-term (organizational) and short-term (activational) benefits of testosterone.
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Affiliation(s)
- Brooke E Pasanen
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - Jordan M Tomkinson
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - Trevor J Dufner
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - Chan Woong Park
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - John S Fitzgerald
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - Grant R Tomkinson
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA.,Alliance for Research in Exercise, Nutrition and Activity (ARENA), Allied Health and Human Performance, University of South Australia, Adelaide, South Australia, Australia
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11
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Di Corrado D, Buscemi A, Magnano P, Maldonato NM, Tusak M, Coco M. Mood States and Performance in Elite Canoe Polo Players: The Mediating Role of Stress. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:4494. [PMID: 33922639 PMCID: PMC8122864 DOI: 10.3390/ijerph18094494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 11/22/2022]
Abstract
Sport performance is characterized by competitive stressful conditions that elicit emotional states. The purpose of the study was to examine whether stress mediated the relationship between mood states and performance. Thirty-two elite canoe polo players from four different Italian teams (16 senior males and 16 senior females), aged between 29 and 38 years old (M = 32.3, SD = 2.71), participated in the study. Measures included level of psychological stress, six mood dimensions, and performance outcome. We also detected the digit ratio-the lower second-to-fourth digit length (2D:4D) ratio-as it was demonstrated to be correlated to high sports performance. The assessment took place one day before the first game of the national competition "ITALY CUP". Male athletes reported lower scores on dysfunctional emotion-related states and on 2D:4D ratio than female athletes. The results of the mediation analysis showed that psychological stress plays a mediating role between moods and performance. Overall, given the limited literature, the findings supported an integrative approach to the study of the linkage between emotion and action in canoe polo.
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Affiliation(s)
- Donatella Di Corrado
- Department of Sport Sciences, Kore University, Cittadella Universitaria, 94100 Enna, Italy
| | - Andrea Buscemi
- Study Center of Italian Osteopathy and Horus Social Cooperative, 95100 Catania, Italy;
| | - Paola Magnano
- Faculty of Human and Social Sciences, Kore University, 94100 Enna, Italy;
| | - Nelson Mauro Maldonato
- Department of Neuroscience and Reproductive and Odontostomatological Sciences, University of Naples Federico II, 80138 Naples, Italy;
| | - Matej Tusak
- Department of Social and Humanistic Sciences in Sport, Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia;
| | - Marinella Coco
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy;
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12
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The Second-to-Fourth Digit (2D:4D) Ratio of Male Combat Athletes is Associated with the Choice of Sport. J Hum Kinet 2021; 78:59-66. [PMID: 34025864 PMCID: PMC8120968 DOI: 10.2478/hukin-2020-0083] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The second-to-fourth-digit (2D:4D) ratio has been widely used as a putative marker of prenatal exposure to testosterone in health, behavioral and sport sciences, but it has only been used few times regarding combat athletes. This study involved 200 male elite combat athletes (Olympic wrestling, kickboxing, judo, taekwondo and karate) and 179 males not participating in any sports. The lengths of the index finger (2D) and ring (4D) finger were measured using computer-assisted image analysis (AutoMetric 2.2 software). The 2D:4D ratio of combat athletes was significantly lower than that of the controls. Moreover, a lower 2D:4D ratio was found among wrestlers, judo athletes and kickboxers than in the control group, and a higher 2D:4D ratio was found, but with borderline significance, among karate and taekwondo athletes. Moreover, multivariate analysis adjusted for age showed that judo, Olympic wrestling and kickboxing athletes combined had 2D:4D ratios significantly lower (by 0.035 on average) than those of the rest of the subjects and that karate and taekwondo athletes together had 2D:4D ratios significantly higher (by 0.014 on average) than those of the rest of the subjects. The research results and literature review indicate that knowledge about the functional meaning of the 2D:4D ratio is still too fragmentary and it is too early to use the 2D:4D ratio in the selection of sport talent; however, it may be a useful criteria when screening prospective athletes to be recruited to a team. That is why 2D:4D reference values should be defined for particular sports.
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13
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Savage D, Chan HF, Moy N, Schaffner M, Torgler B. Personality and individual characteristics as indicators of lifetime climbing success among Everest mountaineers. PERSONALITY AND INDIVIDUAL DIFFERENCES 2020. [DOI: 10.1016/j.paid.2020.110044] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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14
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Stibbard-Hawkes DNE. No Association between 2D:4D Ratio and Hunting Success among Hadza Hunters. HUMAN NATURE (HAWTHORNE, N.Y.) 2020; 31:22-42. [PMID: 31838723 DOI: 10.1007/s12110-019-09359-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The ratio of index- and ring-finger lengths (2D:4D ratio) is thought to be related to prenatal androgen exposure, and in many, though not all, populations, men have a lower average digit ratio than do women. In many studies an inverse relationship has been observed, among both men and women, between 2D:4D ratio and measures of athletic ability. It has been further suggested that, in hunter-gatherer populations, 2D:4D ratio might also be negatively correlated with hunting ability, itself assumed to be contingent on athleticism. This hypothesis has been tested using endurance running performance among runners from a Western, educated, and industrialized population as a proximate measure of hunting ability. However, it has not previously been tested among actual hunter-gatherers using more ecologically valid measures of hunting ability and success. The current study addresses this question among Tanzanian Hadza hunter-gatherers. I employ a novel method of assessing hunting reputation that, unlike previous methods, allows granular distinctions to be made between hunters at all levels of perceived ability. I find no statistically significant relationship between digit ratio and either hunting reputation or two important hunting skills. I confirm that Hadza men have higher mean 2D:4D ratios than men in many Western populations. I discuss the notion that 2D:4D ratio may be the consequence of an allometric scaling relationship between relative and absolute finger lengths. Although it is difficult to draw clear conclusions from these results, the current study provides no support for the theorized relationship between 2D:4D ratio and hunting skill.
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Eklund E, Ekström L, Thörngren JO, Ericsson M, Berglund B, Hirschberg AL. Digit Ratio (2D:4D) and Physical Performance in Female Olympic Athletes. Front Endocrinol (Lausanne) 2020; 11:292. [PMID: 32528408 PMCID: PMC7247813 DOI: 10.3389/fendo.2020.00292] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 04/17/2020] [Indexed: 01/14/2023] Open
Abstract
Background: The second to fourth digit ratio (2D:4D ratio) is suggested to be a negative correlate of prenatal testosterone. Little is known about the role of the 2D:4D ratio in relation to serum and urinary androgens for physical performance in female athletes. We aimed to compare the 2D:4D ratio in female Olympic athletes with sedentary controls, and to investigate the 2D:4D ratio in relation to serum and urinary androgens and physical performance in the athletes. Methods: This cross-sectional study included 104 Swedish female Olympic athletes participating in power, endurance and technical sports and 117 sedentary controls. The 2D:4D ratio was calculated using direct digit measurements. Serum androgens and urinary androgen metabolites were analyzed by liquid chromatography-tandem mass spectrometry. The athletes performed standardized physical performance tests and body composition was established by dual-energy X-ray absorptiometry. Results: The 2D:4D ratio was significantly lower in the athletes compared with controls although serum testosterone levels were comparable between groups and within normal reference values. The 2D:4D ratio correlated negatively with urinary levels of testosterone glucuronide and 5α- and 5βAdiol-17G, whereas there were no correlations to serum androgen levels. Furthermore, the 2D:4D ratio correlated negatively with strength tests and positively with 3,000-meter running in the athletes. Conclusion: Female Olympic athletes had a lower 2D:4D ratio, possibly reflecting a higher prenatal androgen exposure, than sedentary controls. Furthermore, the 2D:4D ratio was related to urinary levels of androgen metabolites and physical performance in the athletes but not to serum androgen levels. It is suggested that the 2D:4D ratio could reflect androgen metabolism and may be of importance for sporting success in female athletes.
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Affiliation(s)
- Emma Eklund
- Department of Women's and Children's Health, Division of Obstetrics and Gynecology, Karolinska Institutet, Stockholm, Sweden
| | - Lena Ekström
- Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - John-Olof Thörngren
- Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Magnus Ericsson
- Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Bo Berglund
- Department of Internal Medicine, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
| | - Angelica Lindén Hirschberg
- Department of Women's and Children's Health, Division of Obstetrics and Gynecology, Karolinska Institutet, Stockholm, Sweden
- Department of Gynecology and Reproductive Medicine, Karolinska University Hospital, Stockholm, Sweden
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16
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Maturational Development as a Key Aspect in Physiological Performance and National-Team Selection in Elite Male Basketball Players. Int J Sports Physiol Perform 2019; 14:902-910. [PMID: 30569768 DOI: 10.1123/ijspp.2018-0681] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 11/27/2018] [Accepted: 12/04/2018] [Indexed: 11/18/2022]
Abstract
PURPOSE To determine the discriminators as variables to select the under-16 national-team players and to examine the influence of biological age on physical/technical parameters among young basketball players. METHODS Thirty-four under-15 male basketball players performed several anthropometrical (height, wingspan, body mass, and fingers length) and physical (jumping, sprinting, throwing, flexibility, change-of-direction speed, and aerobic fitness) tests during the under-15 male national-team training camp. Maturity offset, lower-limb asymmetry index, and power outputs for jumping and sprinting were also computed. In addition, game performance was taken into consideration using game-related statistics (assists, turnovers, steals, rebounds, blocks, and points) of 5 games of during the previous regional tournament (April 2016). Cluster analysis was used to analyze the between-maturation status (prepubertal, pubertal, and postpubertal) differences in physical parameters. RESULTS The postpubertals showed a significantly better performance in power outputs (jumping and sprinting), throwing abilities, and blocks, whereas prepubertal performed significantly better in aerobic fitness and assists. Receiver-operating-characteristic curve confirmed maturational status (area under the curve [AUC] = 0.804; P < .05) and training experience (AUC = 0.789; P < .05) as the most important attributes in predicting under-16 national-team selection. Players with more than 5.5 years of training experience and less than 1.4 y to the age at peak height velocity were most likely to be selected. CONCLUSION Maturational status seems to be a key variable that increases the probability of selection for the Portuguese under-16 national team.
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Misiak M, Butovskaya M, Oleszkiewicz A, Sorokowski P. Digit ratio and hand grip strength are associated with male competition outcomes: A study among traditional populations of the Yali and Hadza. Am J Hum Biol 2019; 32:e23321. [PMID: 31512345 DOI: 10.1002/ajhb.23321] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 08/17/2019] [Accepted: 08/28/2019] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVES Indirect measures of physiological features, such as digit ratio and hand grip strength (HGS), are associated with the outcome of male competition activities. However, most of the studies were conducted in developed and industrialized societies. We tested the hypothesis that both digit ratio and HGS are associated with performance in male-specific activities in two traditional preindustrial societies: Yali and Hadza. METHODS To measure masculine behavioral traits, we determined warriorship status (Yali; n = 49) and assessed hunting skills (Yali n = 47 and Hadza n = 49). We also assessed the digit ratio and HGS of each male. We conducted our analyses using the Bayesian approach. RESULTS Bayesian regression models indicated that greater hand grip strength is associated with better hunting outcomes among Hadza males. We did not find a similar link for the Yali. We found anecdotal evidence for the link between left hand digit ratio and the number of birds hunted by Hadza. We found no evidence for the link between digit ratio and performance in male-male competition. CONCLUSIONS Our results suggest that male-male competition outcomes are determined by upper body strength, but only in the Hadza population. We also found limited support for the hypothesis that digit ratio is associated with hunting success among the Hadza. We found no support for the hypothesis concerning the digit ratio or HGS among the Yali. Our research provides partial support for the evolutionary hypotheses based on studies conducted in industrialized populations.
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Affiliation(s)
- Michał Misiak
- Faculty of Historical and Pedagogical Sciences, Institute of Psychology, University of Wroclaw, Wroclaw, Poland
| | - Marina Butovskaya
- Institute of Ethnology and Anthropology, Russian Academy of Sciences, Moscow, Russia
| | - Anna Oleszkiewicz
- Faculty of Historical and Pedagogical Sciences, Institute of Psychology, University of Wroclaw, Wroclaw, Poland.,Department of Otorhinolaryngology, Smell and Taste Clinic, Dresden, Germany
| | - Piotr Sorokowski
- Faculty of Historical and Pedagogical Sciences, Institute of Psychology, University of Wroclaw, Wroclaw, Poland
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18
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Arede J, Esteves P, Ferreira AP, Sampaio J, Leite N. Jump higher, run faster: effects of diversified sport participation on talent identification and selection in youth basketball. J Sports Sci 2019; 37:2220-2227. [PMID: 31164046 DOI: 10.1080/02640414.2019.1626114] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The aims of this study were to examine the medium-term effects of previous experiences during early stages of sport development on physical capacities of under-13 (U-13) talented basketball players and, to identify variables that discriminated under-14 (U-14) national team training camp selection. Anthropometrical and physical measurements were collected during a basketball training camp. Previous sport experiences (6-10 years), maturity offset, power outputs for jumping and sprinting were determined. A cluster analysis was used to allocate the subjects according to their different levels of sport experiences (more specialized vs. less specialized) to allow creating a dummy variable for the subsequent analysis of the physical variables. A stepwise discriminant analysis was computed to identify the construct that best classifies selected and non-selected players for U-14 national team training camp. The less specialized group outscored more specialized in all physical parameters, irrespectively of gender. The Abalakov Jump Peak Power and Predicted Adult Height (PAH) could successfully discriminate selected from non-selected players for U-14 national team training camp in boys and PAHin girls. The diversified and non-specific sport stimulus during early ages seem to be determinant to the acquisition and development of fundamental movement skills of talented basketball players.
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Affiliation(s)
- Jorge Arede
- a Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, University of Trás-os-Montes and Alto Douro , Vila Real , Portugal
| | - Pedro Esteves
- a Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, University of Trás-os-Montes and Alto Douro , Vila Real , Portugal.,b School of Education, Communication and Sport, Polytechnic Institute of Guarda , Guarda , Portugal
| | | | - Jaime Sampaio
- a Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, University of Trás-os-Montes and Alto Douro , Vila Real , Portugal
| | - Nuno Leite
- a Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, University of Trás-os-Montes and Alto Douro , Vila Real , Portugal
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19
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Agha-Alinejad H, Farzad B, Akbari M, Moffit DM, Dakhili A. Digit ratios and motor and health-related fitness in pre-adolescent females. Ann Hum Biol 2019; 46:225-230. [PMID: 31106581 DOI: 10.1080/03014460.2019.1620332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Background: Assessing different aspects of physical fitness in children whose abilities are undeveloped and their associations with second-to-fourth digit ratio (2D:4D) may better determine the potential athleticism of an individual.Aim: The purpose of the study was to examine relationships between the digit ratios and selected motor and health-related fitness parameters in a large sample of pre-adolescent females.Subjects and methods: Participants included 8-12 year old Iranian and Afghan girls. The length of the left and right second and fourth digits was measured by scanning and computer-assisted image analysis. Motor- and health-related fitness tests were evaluated.Results: No significant correlations were noted between right 2D:4D ratio and physical fitness components. Left 2D:4D and physical fitness components were not correlated, with the exception of handgrip strength (r = -0.193). However, right and left second digit lengths were negatively correlated with predicted VO2max (p ≤ 0.01). In addition, right-left 2D:4D was significantly negatively correlated with flexibility, and significantly positively correlated with height and body fat percentage.Conclusion: In contrast to previous investigations, it seems that left 2D:4D is a predictor of strength, but not aerobic exercise. It is suggested there may be a potential relationship between prenatal androgen exposure and high flexibility, low body fat percentage and the generation of muscular strength in pre-adolescent females.
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Affiliation(s)
- Hamid Agha-Alinejad
- Department of Physical Education and Sports Science, Faculty of Humanities, Tarbiat Modares University, Tehran, Iran
| | - Babak Farzad
- Neuroscience Research Center, Iran University of Medical Sciences, Tehran, Iran.,Department of Physical Education & Sports Science, Azad University, Tehran North Branch, Tehran, Iran
| | - Mina Akbari
- Department of Exercise Physiology, Faculty of Physical Education & Sports Science, Azad University, Tehran Central Branch, Tehran, Iran
| | - Dani M Moffit
- Department of Sport Science and Physical Education, Idaho State University, Pocatello, ID, USA
| | - Amirbahador Dakhili
- Department of Physical Education and Sports Science, Faculty of Humanities, Tarbiat Modares University, Tehran, Iran
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20
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Klapprodt KL, Fitzgerald JS, Short SE, Manning JT, Tomkinson GR. Relationships between the digit ratio (2D:4D) and game-related statistics in professional and semi-professional male basketball players. Am J Hum Biol 2018; 30:e23182. [PMID: 30251289 DOI: 10.1002/ajhb.23182] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/20/2018] [Accepted: 08/21/2018] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVES The primary aim of this study was to examine relationships between digit ratio (2D:4D) and game-related statistics in professional and semi-professional male basketball players. The secondary aim was to quantify differences in mean 2D:4Ds between starting and reserve players. METHODS Using a cross-sectional design, 93 male basketball players from the professional Australian National Basketball League and the semi-professional South Australian Premier League were measured in-season for height, mass, and 2D:4D, with game-related statistics collected end-season. Linear relationships between right and left 2D:4Ds and game-related statistics were quantified using nonparametric partial correlations, and differences in mean 2D:4Ds between starting and reserve players were quantified using analysis of covariance (ANCOVA). All partial correlations and ANCOVAs were adjusted for playing experience, body size, and competitive standard. RESULTS 2D:4D was a weak to moderate negative correlate of points scored and assists-to-turnovers ratio, indicating that males with lower 2D:4Ds were generally better offensively as they recorded more points and assists relative to turnovers. The difference in mean 2D:4D between starting and reserve players was negligible. CONCLUSIONS 2D:4D was favorably correlated with open-skill sports performance, as evidenced by the better offensive statistics of male basketball players with lower 2D:4Ds. These results probably reflect the organizational benefits of prenatal testosterone and indicate that 2D:4D may be a useful complement to traditional physical, physiological, skill, and behavioral predictors of basketball success.
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Affiliation(s)
- Katelyn L Klapprodt
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota
| | - John S Fitzgerald
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota
| | - Sandra E Short
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota
| | - John T Manning
- Applied Sports, Technology, Exercise, and Medicine (A-STEM), Swansea University, Swansea, United Kingdom
| | - Grant R Tomkinson
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota.,Alliance for Research in Exercise, Nutrition and Activity (ARENA), School of Health Sciences and Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia
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21
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Hsu CC, Fong TH, Chang HM, Su B, Chi CP, Kan NW, Hsu MC. Low Second-To-Fourth Digit Ratio Has High Explosive Power? A Prepubertal Study. J Strength Cond Res 2018; 32:2091-2095. [DOI: 10.1519/jsc.0000000000002435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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22
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Keshavarz M, Bayati M, Farzad B, Dakhili A, Agha-Alinejad H. The Second to Fourth Digit Ratio in Elite and Non-Elite Greco-Roman Wrestlers. J Hum Kinet 2017; 60:145-151. [PMID: 29339994 PMCID: PMC5765794 DOI: 10.1515/hukin-2017-0097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A low second-to-fourth digit ratio (2D:4D) has been reported to correlate with high performance and athletic potential of an individual in sport. It has been suggested that 2D:4D is a relatively weak predictor of strength and a stronger predictor of efficiency in aerobic exercise. Comparing extreme groups on a continuum of sports performance requiring high power (physical strength) output would be helpful to resolve this issue. Therefore, the purpose of the present study was to compare the 2D:4D ratio of world-class elite Greco-Roman wrestlers (n = 10) taking part in Olympic fitness camps in 2013 with the 2D:4D ratio of non-elite collegiate wrestlers (n = 20), and age-matched sedentary males (n = 40). The 2D:4D ratios of elite wrestlers were lower compared to non-elite athletes (p < 0.01, right hand d = 1.70, left hand d = 1.67) and the control group (p < 0.0001, right hand d = 3.16, left hand d = 2.00). No significant differences were noted among the groups for right - left 2D:4D. We concluded that 2D:4D may discriminate between non-elite and world-class wrestlers. We also suggest that a low 2D:4D ratio could be linked to performance potential in wrestlers. As such, 2D:4D may provide additional information, which is valuable in determining the potential athleticism of an individual, when it is used in conjunction with other measures.
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Affiliation(s)
- Mohammad Keshavarz
- Department of Physical Education, Faculty of Humanities, Tarbiat Modares University, Tehran, Iran
- Mohammad Keshavarz Department of Physical Education, Faculty of Humanities, Tarbiat Modares University. Jalal AleAhmad Highway, Nasr Bridge, Tehran, Iran. Phone number: +98 912 759 3799
| | - Mahdi Bayati
- Department of Exercise Physiology, Sports Medicine Research Center, Sport Sciences Research Institute, Tehran, Iran
| | - Babak Farzad
- Neuroscience Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Amirbahador Dakhili
- Department of Physical Education, Faculty of Humanities, Tarbiat Modares University, Tehran, Iran
| | - Hamid Agha-Alinejad
- Department of Physical Education, Faculty of Humanities, Tarbiat Modares University, Tehran, Iran
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23
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Joyce CW, O' Regan A, Kelly JL, O' Shaughnessy M. Fight Bite Injuries: Aggressive Tendencies Associated with Smaller Second to Fourth Digit Ratio. J Hand Surg Asian Pac Vol 2017; 22:452-456. [PMID: 29117839 DOI: 10.1142/s0218810417500496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Fight bite injuries are typically sustained by young, combative males and are the direct consequence of an aggressive act. Second to fourth digit ratios (2D:4D) are dependent on prenatal androgen exposure and lower ratios have been shown to be linked to various psychological and physical traits, including aggression. The aim of this study was to examine the 2D:4D ratios in a cohort of patients with fight bite injuries and compare these to an age and gender-matched control group. METHODS The 2D:4D ratios were calculated using plain films of the hand from 133 patients (122 males, 11 females) with fight bite injuries. A further 133 radiographs were obtained from patients that did not have fight bite injuries and digit ratios were calculated in the same fashion. Statistical analysis was then carried out to compare the 2D:4D ratios between the different groups. RESULTS The 2D:4D ratios for male fight bite patients was significantly smaller than the male control group (p < 0.05). No significant difference was observed between the female fight bite patients and the female control group (p > 0.05). CONCLUSIONS Fight bite injuries are usually sustained as a result of aggression. 2D:4D ratios are reflect intrauterine androgen exposure and low ratios have been linked to aggressive tendencies. We have demonstrated that male patients who sustained fight bite injuries have a lower 2D:4D ratio then the general population, thereby suggesting that exposure to prenatal androgens can lead to aggressive tendencies in adulthood. This suggests that lower ratios may predict a predisposition to acts of aggression, and as such result in an increased likelihood of sustaining an injury such as a fight bite.
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Affiliation(s)
- Cormac W Joyce
- * Department of Plastic, Reconstructive and Hand Surgery, Cork, Ireland
| | - Andrew O' Regan
- * Department of Plastic, Reconstructive and Hand Surgery, Cork, Ireland
| | - Jack L Kelly
- † Department of Plastic, Reconstructive and Hand Surgery, Galway, Ireland
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Reed S, Meggs J. Examining the effect of prenatal testosterone and aggression on sporting choice and sporting longevity. PERSONALITY AND INDIVIDUAL DIFFERENCES 2017. [DOI: 10.1016/j.paid.2017.04.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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25
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Yokoi T, Uemura T, Kazuki K, Onode E, Shintani K, Okada M, Nakamura H. Low second to fourth digit ratio in Dupuytren disease. Medicine (Baltimore) 2017; 96:e7801. [PMID: 28816972 PMCID: PMC5571709 DOI: 10.1097/md.0000000000007801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The ratio of the lengths of the second and fourth digits (2D:4D) has been described as reflecting endogenous prenatal androgen exposure. In general, 2D:4D is lower in men than in women and has potential as a biomarker or predictor for various diseases, athletic ability, and academic performance. Dupuytren disease has digital flexion contractures and is known to predominate in men, but the pathogenesis of the disease remains unclear. To clarify the relationships between Dupuytren disease and endogenous androgens, we performed a retrospective analysis of hand radiographs to investigate 2D:4D in Dupuytren disease. The study included male patients with Dupuytren disease (n = 22) and a control group (n = 18) of male patients with carpal tunnel syndrome. Only unaffected hands, without contractures or osteoarthritis, were evaluated for the purpose of radiographic assessment. The lengths of the phalanx and metacarpal bones in the second and fourth digits were measured by 2 independent observers who each performed 2 sets of measurements separated by a minimum 1-week interval. The 2D:4D was calculated separately for the phalanges and metacarpals, and a combined (phalanx + metacarpal) 2D:4D was also calculated. The reliability of the observer measurements was established using the intraclass correlation coefficient, and both the intra- and interobserver reliability showed excellent agreement. We found that compared with control group, the Dupuytren disease group had significantly lower phalanx and combined 2D:4D. These findings suggest that endogenous prenatal androgens could contribute to the development of Dupuytren disease, leading to its characteristic clinical presentation predominantly in men and affecting the ulnar rays.
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Affiliation(s)
- Takuya Yokoi
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka
| | - Takuya Uemura
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka
| | | | - Ema Onode
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka
| | - Kosuke Shintani
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka
| | - Mitsuhiro Okada
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka
| | - Hiroaki Nakamura
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka
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26
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Georgiev AV, Ryan CP, Gettler LT, McDade TW, Kuzawa CW. Second‐to‐fourth digit ratio (2D:4D) is unrelated to measures of somatic reproductive effort among young men from Cebu, the Philippines. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2017; 163:437-445. [DOI: 10.1002/ajpa.23215] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 02/24/2017] [Accepted: 03/10/2017] [Indexed: 12/18/2022]
Affiliation(s)
| | - Calen P. Ryan
- Department of AnthropologyNorthwestern UniversityEvanston Illinois
| | - Lee T. Gettler
- Department of AnthropologyUniversity of Notre DameNotre Dame Indiana
- The Eck Institute for Global HealthUniversity of Notre DameNotre Dame Indiana
| | - Thomas W. McDade
- Department of AnthropologyNorthwestern UniversityEvanston Illinois
- Institute for Policy ResearchNorthwestern UniversityEvanston Illinois
| | - Christopher W. Kuzawa
- Department of AnthropologyNorthwestern UniversityEvanston Illinois
- Institute for Policy ResearchNorthwestern UniversityEvanston Illinois
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Kim TB, Kim KH. Why is digit ratio correlated to sports performance? J Exerc Rehabil 2016; 12:515-519. [PMID: 28119871 PMCID: PMC5227311 DOI: 10.12965/jer.1632862.431] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/07/2016] [Indexed: 11/22/2022] Open
Abstract
Second to fourth digit ratio is the ratio of second to fourth digit length. It has been known that digit ratio is sexually dimorphic in humans, such that males tend to have lower digit ratio (longer fourth digits relative to second digits) than females. Digit ratio is thought to be a biomarker of the balance between fetal testosterone (FT) and fetal estrogen (FE) in a relatively narrow developmental window at the end of the first trimester of pregnancy. On the contrary, the relationships between digit ratio and levels of sex steroids in adults are not clear. Most correlational studies between digit ratio and adult sex steroids have revealed that this association is statistically not significant. However, for many years, a lot of researches showed negative relationships between digit ratio and sports performance such as rugby, surfing, rowing, sprinting, endurance, and hand grip strength. Here, we discuss possible mechanisms about the relationships between digit ratio and sports performance.
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Affiliation(s)
- Tae Beom Kim
- Department of Urology, Gachon University Gil Medical Center, Gachon University School of Medicine, Incheon, Korea
| | - Khae Hawn Kim
- Department of Urology, Gachon University Gil Medical Center, Gachon University School of Medicine, Incheon, Korea
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Second to Fourth Digit Ratios in Plastic Surgery. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2016; 4:e602. [PMID: 27104101 PMCID: PMC4801099 DOI: 10.1097/gox.0000000000000586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/02/2015] [Indexed: 11/26/2022]
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Ellis L, Skorska MN, Bogaert AF. Handedness, sexual orientation, and somatic markers for prenatal androgens: Are southpaws really that gay? Laterality 2016; 22:157-180. [DOI: 10.1080/1357650x.2016.1151024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Ellis L, Lykins A, Hoskin A, Ratnasingam M. Putative Androgen Exposure and Sexual Orientation: Cross-Cultural Evidence Suggesting a Modified Neurohormonal Theory. J Sex Med 2015; 12:2364-77. [PMID: 26663858 DOI: 10.1111/jsm.13070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION According to neurohormonal theory, prenatal androgens are key determinants of sexual orientation. As a reputed marker for prenatal androgens, the 2D:4D finger length ratio has been used in more than a dozen studies to test the hypothesis that prenatal androgens influence sexual orientation. Findings have been very inconsistent. AIM The present study sought to retest the hypothesis that 2D:4D and sexual orientation are related is a manner consistent with neurohormonal theory. METHODS A 2D:4D measure (of the right hand) along with four additional somatic markers of androgen exposure (height, physical strength, muscularity, and athletic ability) with samples of college students in Malaysia (N = 2,058) and the United States (N = 2,511). The five androgen measures were factor analyzed, resulting in a two-factor solution: Factor 1 consisted of strength, muscularity, and athletic ability (the muscular coordination factor), and Factor 2 was comprised of the r2D:4D and adult height (the bone growth factor). MAIN OUTCOME MEASURES Sexual orientation was measured by asking each respondent the extent to which they were sexually attracted to males and the extent to which they were sexually attracted to females, both on 11-point scales. RESULTS When the countries and sexes were analyzed separately, neither the r2D:4D measure nor Factor 2 correlated with sexual orientation to significant degrees. Instead, it was the muscular coordination factor that correlated the best. Support was found for the hypothesis that prenatal androgens influence sexual orientation, but the nature of these influences was more complex than neurohormonal theory predicted. CONCLUSION A modified theory is needed and presented to accommodate the results from this study.
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Affiliation(s)
- Lee Ellis
- University of Malaya, Kuala Lumpur, Malaysia
| | - Amy Lykins
- University of New England, Armidale, NSW, Australia
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Bove R, Malik MT, Diaz-Cruz C, Chua A, Saraceno TJ, Bargiela D, Greeke E, Glanz BI, Healy BC, Chitnis T. The 2D:4D ratio, a proxy for prenatal androgen levels, differs in men with and without MS. Neurology 2015; 85:1209-13. [PMID: 26341868 DOI: 10.1212/wnl.0000000000001990] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 05/07/2015] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine whether the 2D:4D ratio (ratio of the second and fourth digit lengths), a proxy for lower prenatal androgen to estrogen ratio, differs in men with and without multiple sclerosis (MS) using a case-control study design. METHODS We obtained 2 digital scans of the right hand for men with MS presenting to a scheduled clinic visit at a large MS referral center, and for men without autoimmune or endocrine diseases. All individuals were aged 18 to 65 years, right-handed, and reported no prior digit trauma. We calculated a mean 2D:4D ratio using digital calipers. In participants with MS, we assessed age at first MS symptoms, MS type, and the MS Severity Score; 51 had provided a testosterone level within 10 years of symptom onset. Our primary analysis was a cross-sectional comparison of the 2D:4D ratio between men with and without MS, using a 2-sample t test for independent samples assuming unequal variance. RESULTS In total, we scanned 137 men with MS and 145 men without MS. A statistically significant association between 2D:4D ratio and MS status was observed in the univariate logistic regression model (p<0.05). These differences were not associated with age or race, which differed between the 2 groups. In participants with MS, the 2D:4D ratio was not correlated with MS type, age at first symptoms, or MS Severity Score (p>0.15 for each), and it was not correlated with adult testosterone levels (r=0.06, p=0.68, n=51). CONCLUSIONS During the prenatal period, low androgens could represent a risk factor for MS.
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Affiliation(s)
- Riley Bove
- From the Partners Multiple Sclerosis Center (R.B., M.T.M., C.D.-C., A.C., T.J.S., D.B., E.G., B.I.G., B.C.H., T.C.), Department of Neurology, Brigham and Women's Hospital, Brookline; Harvard Medical School (R.B., B.I.G., B.C.H., T.C.), Boston; Ann Romney Center for Neurologic Diseases (R.B., D.B., B.I.G., B.C.H., T.C.), Harvard Medical School, Boston; and Massachusetts General Hospital Biostatistics Center (B.C.H.), Boston, MA
| | - Muhammed T Malik
- From the Partners Multiple Sclerosis Center (R.B., M.T.M., C.D.-C., A.C., T.J.S., D.B., E.G., B.I.G., B.C.H., T.C.), Department of Neurology, Brigham and Women's Hospital, Brookline; Harvard Medical School (R.B., B.I.G., B.C.H., T.C.), Boston; Ann Romney Center for Neurologic Diseases (R.B., D.B., B.I.G., B.C.H., T.C.), Harvard Medical School, Boston; and Massachusetts General Hospital Biostatistics Center (B.C.H.), Boston, MA
| | - Camilo Diaz-Cruz
- From the Partners Multiple Sclerosis Center (R.B., M.T.M., C.D.-C., A.C., T.J.S., D.B., E.G., B.I.G., B.C.H., T.C.), Department of Neurology, Brigham and Women's Hospital, Brookline; Harvard Medical School (R.B., B.I.G., B.C.H., T.C.), Boston; Ann Romney Center for Neurologic Diseases (R.B., D.B., B.I.G., B.C.H., T.C.), Harvard Medical School, Boston; and Massachusetts General Hospital Biostatistics Center (B.C.H.), Boston, MA
| | - Alicia Chua
- From the Partners Multiple Sclerosis Center (R.B., M.T.M., C.D.-C., A.C., T.J.S., D.B., E.G., B.I.G., B.C.H., T.C.), Department of Neurology, Brigham and Women's Hospital, Brookline; Harvard Medical School (R.B., B.I.G., B.C.H., T.C.), Boston; Ann Romney Center for Neurologic Diseases (R.B., D.B., B.I.G., B.C.H., T.C.), Harvard Medical School, Boston; and Massachusetts General Hospital Biostatistics Center (B.C.H.), Boston, MA
| | - Taylor J Saraceno
- From the Partners Multiple Sclerosis Center (R.B., M.T.M., C.D.-C., A.C., T.J.S., D.B., E.G., B.I.G., B.C.H., T.C.), Department of Neurology, Brigham and Women's Hospital, Brookline; Harvard Medical School (R.B., B.I.G., B.C.H., T.C.), Boston; Ann Romney Center for Neurologic Diseases (R.B., D.B., B.I.G., B.C.H., T.C.), Harvard Medical School, Boston; and Massachusetts General Hospital Biostatistics Center (B.C.H.), Boston, MA
| | - David Bargiela
- From the Partners Multiple Sclerosis Center (R.B., M.T.M., C.D.-C., A.C., T.J.S., D.B., E.G., B.I.G., B.C.H., T.C.), Department of Neurology, Brigham and Women's Hospital, Brookline; Harvard Medical School (R.B., B.I.G., B.C.H., T.C.), Boston; Ann Romney Center for Neurologic Diseases (R.B., D.B., B.I.G., B.C.H., T.C.), Harvard Medical School, Boston; and Massachusetts General Hospital Biostatistics Center (B.C.H.), Boston, MA
| | - Emily Greeke
- From the Partners Multiple Sclerosis Center (R.B., M.T.M., C.D.-C., A.C., T.J.S., D.B., E.G., B.I.G., B.C.H., T.C.), Department of Neurology, Brigham and Women's Hospital, Brookline; Harvard Medical School (R.B., B.I.G., B.C.H., T.C.), Boston; Ann Romney Center for Neurologic Diseases (R.B., D.B., B.I.G., B.C.H., T.C.), Harvard Medical School, Boston; and Massachusetts General Hospital Biostatistics Center (B.C.H.), Boston, MA
| | - Bonnie I Glanz
- From the Partners Multiple Sclerosis Center (R.B., M.T.M., C.D.-C., A.C., T.J.S., D.B., E.G., B.I.G., B.C.H., T.C.), Department of Neurology, Brigham and Women's Hospital, Brookline; Harvard Medical School (R.B., B.I.G., B.C.H., T.C.), Boston; Ann Romney Center for Neurologic Diseases (R.B., D.B., B.I.G., B.C.H., T.C.), Harvard Medical School, Boston; and Massachusetts General Hospital Biostatistics Center (B.C.H.), Boston, MA
| | - Brian C Healy
- From the Partners Multiple Sclerosis Center (R.B., M.T.M., C.D.-C., A.C., T.J.S., D.B., E.G., B.I.G., B.C.H., T.C.), Department of Neurology, Brigham and Women's Hospital, Brookline; Harvard Medical School (R.B., B.I.G., B.C.H., T.C.), Boston; Ann Romney Center for Neurologic Diseases (R.B., D.B., B.I.G., B.C.H., T.C.), Harvard Medical School, Boston; and Massachusetts General Hospital Biostatistics Center (B.C.H.), Boston, MA
| | - Tanuja Chitnis
- From the Partners Multiple Sclerosis Center (R.B., M.T.M., C.D.-C., A.C., T.J.S., D.B., E.G., B.I.G., B.C.H., T.C.), Department of Neurology, Brigham and Women's Hospital, Brookline; Harvard Medical School (R.B., B.I.G., B.C.H., T.C.), Boston; Ann Romney Center for Neurologic Diseases (R.B., D.B., B.I.G., B.C.H., T.C.), Harvard Medical School, Boston; and Massachusetts General Hospital Biostatistics Center (B.C.H.), Boston, MA.
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Crewther B, Cook C, Kilduff L, Manning J. Digit ratio (2D:4D) and salivary testosterone, oestradiol and cortisol levels under challenge: Evidence for prenatal effects on adult endocrine responses. Early Hum Dev 2015; 91:451-6. [PMID: 26025335 DOI: 10.1016/j.earlhumdev.2015.04.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 04/23/2015] [Accepted: 04/25/2015] [Indexed: 01/09/2023]
Abstract
BACKGROUND Digit ratio (2D:4D) is a marker for prenatal sex steroids and a correlate of sporting performance. This association may exist because low 2D:4D is linked to high prenatal levels of testosterone (T) and low oestrogens (E). It was recently suggested that low 2D:4D, and particularly low right-left 2D:4D (or Dr-l), is a marker for T changes in response to physical and aggressive challenges. If correct, this link may in part explain the association between 2D:4D and sports performance. AIMS We tested this hypothesis in adults. STUDY DESIGN Three experimental treatments were completed using a randomised, cross-over design; (i) cycle sprints plus an aggressive video (S+V), (ii) aggressive video plus cycle sprints (V+S), and (iii) a control session. SUBJECTS 24 healthy adults (12 men and 12 women). OUTCOME MEASURES Salivary T, oestradiol (E2) and cortisol (C) levels were measured on six occasions across each session and pooled for analysis. RESULTS The S+V treatment was associated with a rise in T and C levels, and Dr-l was significantly and negatively correlated with T and E2 with these effects confined to men. The right 2D:4D and Dr-l were also negatively correlated with the T/C ratio and Dr-l negatively related to the E2/C ratio in men during the S+V treatment. CONCLUSIONS We suggest that the hormonal responses to a challenge are programmed by prenatal levels of T and E with possible links to sporting performance in adulthood.
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Affiliation(s)
| | - Christian Cook
- The Hamlyn Centre, Imperial College, London, UK; School of Sport, Health and Exercise Science, Bangor University, Gwynedd, UK
| | - Liam Kilduff
- Applied Sports Technology, Exercise and Medicine Research Centre, Swansea University, Swansea, UK
| | - John Manning
- Department of Psychology, Northumbria University, Newcastle-upon-Tyne, UK
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Hsu CC, Su B, Kan NW, Lai SL, Fong TH, Chi CP, Chang CC, Hsu MC. Elite Collegiate Tennis Athletes Have Lower 2D. J Strength Cond Res 2015; 29:822-5. [DOI: 10.1519/jsc.0000000000000681] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Galizzi MM, Nieboer J. Digit ratio (2D:4D) and altruism: evidence from a large, multi-ethnic sample. Front Behav Neurosci 2015; 9:41. [PMID: 25755639 PMCID: PMC4337370 DOI: 10.3389/fnbeh.2015.00041] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 02/05/2015] [Indexed: 11/30/2022] Open
Abstract
We look at the links between the Digit Ratio—the ratio of the length of the index finger to the length of the ring finger—for both right and left hands, and giving in a Dictator Game. Unlike previous studies with exclusively Caucasian subjects, we consider a large, ethnically diverse sample. Our main results are as follows. First, for Caucasian subjects we estimate a significant positive regression coefficient for the right hand digit ratio and a significant negative coefficient for its squared measure. These results replicate the findings of Brañas-Garza et al. (2013), who also observe an inverted U-shaped relationship for Caucasian subjects. Second, we are not able to find any significant association of the right hand digit ratio with giving in the Dictator Game for the other main ethnic groups in our sample, nor in the pooled sample. Third, we find no significant association between giving in the Dictator Game and the left hand digit ratio.
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Affiliation(s)
- Matteo M Galizzi
- Behavioural Research Lab, Department of Social Policy, London School of Economics and Political Science London, UK
| | - Jeroen Nieboer
- Behavioural Research Lab, Department of Social Policy, London School of Economics and Political Science London, UK
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Romann M, Fuchslocher J. Validation of digit-length ratio (2D:4D) assessments on the basis of DXA-derived hand scans. BMC Med Imaging 2015; 15:1. [PMID: 25645550 PMCID: PMC4323124 DOI: 10.1186/s12880-015-0042-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 01/08/2015] [Indexed: 11/10/2022] Open
Abstract
Background The second-to-fourth digit-length ratio (2D:4D) may be a correlate of prenatal sex steroids, and it has been linked to sporting prowess. The aim of the study was to validate dual-energy X-ray-absorptiometry (DXA) as a technique to assess 2D:4D in soccer players under 15 years of age (U-15). Methods Paired X-ray and DXA scans of the left hands of 63 male U-15 elite soccer players (age: 14.0 ± 0.3 years) were performed, and 2D:4D was then compared between the two techniques. The 2D:4D measurements were performed twice by two blinded raters. Intrarater and interrater reliability, as well as agreement between the X-ray and the DXA assessments, were tested. Results Intrarater reliabilities of both raters using X-ray with intraclass correlation coefficients (ICCs) of 0.97 and 0.90 were excellent. Using DXA, the ICCs were 0.90 and 0.91 thus also showing excellent reliability. Interrater reliabilities were excellent using both the X-ray (ICC of 0.94) and the DXA (ICC of 0.90), assessments respectively. Bland-Altman plots demonstrated that the 2D:4D ratios of the two raters did not differ significantly between the X-ray and the DXA assessments. The standard errors of estimate were 0.01 for both techniques. The 95% limits of agreement of ±0.018 (±2.0%) and ±0.023 (±2.6%), respectively, were within the acceptable tolerance of 5%, and showed very good agreement. Conclusion DXA offered a replicable technique for assessing 2D:4D in youth soccer players. Therefore, the DXA technique seems to be an alternative method for evaluating 2D:4D in youth sports.
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Affiliation(s)
- Michael Romann
- Swiss Federal Institute of Sport Magglingen, CH-2532, Magglingen, Switzerland.
| | - Jörg Fuchslocher
- Swiss Federal Institute of Sport Magglingen, CH-2532, Magglingen, Switzerland.
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Kasielska-Trojan A, Antoszewski B. Can digit ratio (2D:4D) studies be helpful in explaining the aetiology of idiopathic gynecomastia? Early Hum Dev 2015; 91:57-61. [PMID: 25543532 DOI: 10.1016/j.earlhumdev.2014.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 11/24/2014] [Accepted: 12/02/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND Aetiology of idiopathic form of gynecomastia is unknown and it has not been established if it is related to factors present at the prenatal period or if it is caused by yet unidentified environmental conditions. OBJECTIVE The aim of this study is to compare digit ratio (2D:4D) in men with idiopathic gynecomastia and unaffected male and female controls from the general population. METHODS The study involved 250 subjects (50 men with idiopathic gynecomastia, 100 control men and 100 control women). Eight measurements were taken: body height, waist and hip circumferences, II and IV digits' lengths (right and left), and body weight, and 4 indices were calculated: BMI, WHR, and 2D:4D for the right and left hand. RESULTS 2D:4D in men with gynecomastia ([median (I-III quartiles)]: 1.03 (1.01-1.04) for right hand and 1.03 (1.01-1.03) for left hand) was significantly different than the ratio in control men [0.97 (0.95-0.99)] for right and left hand) (p<0.0001) and similar to the ratio found in control women [1.02 (1-1.03)] for right and left hand) (p=1). Men with gynecomastia were characterized with higher values of the following variables: weight, waist and hip circumferences, BMI and WHR. Their body height was significantly greater than in women (p<0.0001) but similar to the values observed in control men (p=0.2687). CONCLUSION The findings presented in this study may influence the aetiology-related classification of gynecomastia and justify introducing the new group: "gynecomastia related to the prenatal sex hormones disturbances".
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Affiliation(s)
- Anna Kasielska-Trojan
- Plastic, Reconstructive and Aesthetic Surgery Clinic, Institute of Surgery, Medical University of Lodz, Lodz, Poland.
| | - Bogusław Antoszewski
- Plastic, Reconstructive and Aesthetic Surgery Clinic, Institute of Surgery, Medical University of Lodz, Lodz, Poland
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Hull MJ, Schranz NK, Manning JT, Tomkinson GR. Relationships between digit ratio (2D:4D) and female competitive rowing performance. Am J Hum Biol 2014; 27:157-63. [DOI: 10.1002/ajhb.22627] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 08/10/2014] [Accepted: 09/04/2014] [Indexed: 11/10/2022] Open
Affiliation(s)
- Melissa J. Hull
- Health and Use of Time Group, Sansom Institute for Health Research, Division of Health Sciences; University of South Australia; Adelaide Australia
| | - Natasha K. Schranz
- Health and Use of Time Group, Sansom Institute for Health Research, Division of Health Sciences; University of South Australia; Adelaide Australia
| | - John T. Manning
- Department of Psychology; Northumbria University, Newcastle-Upon Tyne; United Kingdom
| | - Grant R. Tomkinson
- Health and Use of Time Group, Sansom Institute for Health Research, Division of Health Sciences; University of South Australia; Adelaide Australia
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Sudhakar HH, Majumdar P, Umesh V, Panda K. Second to fourth digit ratio is a predictor of sporting ability in elite Indian male kabaddi players. Asian J Sports Med 2014; 5:e23073. [PMID: 25520769 PMCID: PMC4267485 DOI: 10.5812/asjsm.23073] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 02/02/2014] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND To determine the 2D:4D ratio in elite Indian male kabaddi players and compare them with non-athletes. OBJECTIVES Our study was undertaken to find out a possible relation between digit ratio and sporting ability of male kabaddi players. This study also gives an insight into the possible ethnic differences between Indian sports personnel and other populations. PATIENTS AND METHODS Both right and left hands of 33 male kabaddi players attending training camp at the Bangalore regional centre of Sports Authority of India were scanned. Lengths of second and fourth digits were measured and their ratio calculated. Age, weight, height and body mass index matched subjects (25 males) who did not participate in any sports formed the control group. RESULTS A highly significant difference was found in 2D:4D ratios of both the hands with Kabaddi players having a lower ratio compared to their controls. There was no statistically significant difference in 2D:4D (Δ r-l) between Kabaddi players and controls. CONCLUSIONS Kabaddi is an intermediate sport not requiring a high level of endurance but at the same time requires masculine traits because of combating nature of the game. 2D:4D ratios can be used as reliable additional criteria when screening for prospective players to be inducted into the team.
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Affiliation(s)
- Honnamachanahalli H. Sudhakar
- Kempegowda Institute of Medical Sciences, Bangalore, India
- Corresponding author: Honnamachanahalli H. Sudhakar, Kempegowda Institute of Medical Sciences, Bangalore, India. Tel: +91-8026712791, Fax: +91-8026712798, E-mail:
| | | | - Veena Umesh
- Kempegowda Institute of Medical Sciences, Bangalore, India
| | - Kaninika Panda
- Kempegowda Institute of Medical Sciences, Bangalore, India
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Manning J, Kilduff L, Cook C, Crewther B, Fink B. Digit Ratio (2D:4D): A Biomarker for Prenatal Sex Steroids and Adult Sex Steroids in Challenge Situations. Front Endocrinol (Lausanne) 2014; 5:9. [PMID: 24523714 PMCID: PMC3906590 DOI: 10.3389/fendo.2014.00009] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 01/16/2014] [Indexed: 11/13/2022] Open
Abstract
Digit ratio (2D:4D) denotes the relative length of the second and fourth digits. This ratio is considered to be a biomarker of the balance between fetal testosterone (T) and estrogen (E) in a narrow window of early ontogeny. Evidence for this assertion is derived from direct and indirect measures of prenatal hormonal exposure (in experimental animals, via amniotic fluid samples and in the study of sex-typical traits) in relation to 2D:4D. In contrast, the relationships between 2D:4D and levels of sex steroids in adults are less clear, as many correlational studies of 2D:4D and adult sex steroids have concluded that this association is statistically non-significant. Here, we suggest that in order to understand the link between 2D:4D and sex hormones, one must consider both fetal organizing and adult activating effects of T and E. In particular, we hypothesize that 2D:4D correlates with organizing effects on the endocrine system that moderate activating effects in adulthood. We argue that this is particularly evident in "challenging" conditions such as aggressive and sexual encounters, in which individuals show increased levels of T. We discuss this refinement of the 2D:4D paradigm in relation to the links between 2D:4D and sports performance, and aggression.
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Affiliation(s)
- John Manning
- Department of Psychology, Northumbria University, Newcastle upon Tyne, UK
- *Correspondence: John Manning, Department of Psychology, Northumbria University, Newcastle upon Tyne NE1 8ST, UK e-mail:
| | - Liam Kilduff
- Applied Sports Technology, Exercise and Medicine Research Centre, Swansea University, Swansea, UK
| | - Christian Cook
- School of Sport, Health and Exercise Science, Bangor University, Gwynedd, UK
| | | | - Bernhard Fink
- Department of Biological Personality Psychology and Assessment, University of Göttingen, Göttingen, Germany
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Baker J, Kungl AM, Pabst J, Strauß B, Büsch D, Schorer J. Your fate is in your hands? Handedness, digit ratio (2D:4D), and selection to a national talent development system. Laterality 2013; 18:710-8. [DOI: 10.1080/1357650x.2012.755992] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Zhao D, Yu K, Zhang X, Zheng L. Digit ratio (2D:4D) and handgrip strength in Hani ethnicity. PLoS One 2013; 8:e77958. [PMID: 24205044 PMCID: PMC3813549 DOI: 10.1371/journal.pone.0077958] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 09/06/2013] [Indexed: 11/26/2022] Open
Abstract
Introduction The ratio of the length of the second finger to the fourth finger (2D:4D) in humans is considered as a putative marker of prenatal exposure to testosterone, and has been progressively adopted as one useful tool to evaluate the effect of prenatal hormones in some traits such as physical ability. Handgrip strength is one authentic measure of physical ability and is generally used on the anthropological research within an evolutionary viewpoint. Methods Here we present the first evidence on 2D:4D and handgrip strength on adult participants of Hani ethnicity and explore the relationship between digit ratio (2D:4D) and handgrip strength. We examined 2D:4D and handgrip strength of 80 males and 60 females at Bubeng village, in the Yunnan province of China. Results The mean 2D:4D in females was higher than that in males for each hand. Females showed significantly higher 2D:4D than males in the right hand rather than in the left hand. Males displayed significantly higher handgrip strength than females for both hands. Handgrip strength decreased with age for both sexes. A significant negative correlation between 2D:4D and handgrip strength was found in the right hand of males. Conclusion The relationship between 2D:4D and handgrip strength may be attributed to evolutionary drive of sexual selection operating on fetal programming.
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Affiliation(s)
- Dapeng Zhao
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin, China ; College of Life Sciences, Northwest University, Xi'an, China
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Kilduff LP, Hopp RN, Cook CJ, Crewther BT, Manning JT. Digit ratio (2D:4D), aggression, and testosterone in men exposed to an aggressive video stimulus. EVOLUTIONARY PSYCHOLOGY 2013; 11:953-964. [PMID: 24113579 PMCID: PMC10434407 DOI: 10.1177/147470491301100502] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/25/2013] [Indexed: 03/28/2024] Open
Abstract
The relative lengths of the 2(nd) and 4(th) digits (2D:4D) is a negative biomarker for prenatal testosterone, and low 2D:4D may be associated with aggression. However, the evidence for a 2D:4D-aggression association is mixed. Here we test the hypothesis that 2D:4D is robustly linked to aggression in "challenge" situations in which testosterone is increased. Participants were exposed to an aggressive video and a control video. Aggression was measured after each video and salivary free testosterone levels before and after each video. Compared to the control video, the aggressive video was associated with raised aggression responses and a marginally significant increase in testosterone. Left 2D:4D was negatively correlated with aggression after the aggressive video and the strength of the correlation was higher in those participants who showed the greatest increases in testosterone. Left 2D:4D was also negatively correlated to the difference between aggression scores in the aggressive and control conditions. The control video did not influence testosterone concentrations and there were no associations between 2D:4D and aggression. We conclude that 2D:4D moderates the impact of an aggressive stimulus on aggression, such that an increase in testosterone resulting from a "challenge" is associated with a negative correlation between 2D:4D and aggression.
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Affiliation(s)
- Liam P. Kilduff
- Applied Sports Technology, Exercise and Medicine Research Centre, Swansea
University, Swansea, UK
| | - Renato N. Hopp
- Department of Pathology, University Estadual Paulista, Brazil
| | | | | | - John T. Manning
- Applied Sports Technology, Exercise and Medicine Research Centre, Swansea
University, Swansea, UK
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The left hand second to fourth digit ratio (2D:4D) is not related to any physical fitness component in adolescent girls. PLoS One 2013; 8:e59766. [PMID: 23565167 PMCID: PMC3614960 DOI: 10.1371/journal.pone.0059766] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 02/18/2013] [Indexed: 11/26/2022] Open
Abstract
Introduction The second to fourth-digit-ratio (2D:4D), a putative marker of prenatal androgen action and a sexually dimorphic trait, has been suggested to be related with fitness and sports performance, although results are not univocal. Most studies however focus on a single aspect of physical fitness or one sports discipline. Methods In this study the 2D:4D ratio of 178 adolescent girls (age 13,5–18 y) was measured on X-rays of the left hand. The relation between 2D:4D digit ratio and multiple aspects of physical fitness (balance, speed of limb movement, flexibility, explosive strength, static strength, trunk strength, functional strength, running speed/agility, and endurance) was studied by correlation analyses and stepwise multiple regression. For comparison the relation between these physical fitness components and a selected number of objectively measured anthropometric traits (stature, mass, BMI, somatotype components and the Bayer & Bailey androgyny index) are presented alongside the results of 2D:4D digit ratio. Results Left hand 2D:4D digit ratio (0.925±0.019) was not significantly correlated with any of the physical fitness components nor any of the anthropometric variables included in the present study. 2D:4D did not enter the multiple stepwise regression for any of the physical fitness components in which other anthropometric traits explained between 9,2% (flexibility) and 33,9% (static strength) of variance. Conclusion Unlike other anthropometric traits the 2D:4D digit ratio does not seem to be related to any physical fitness component in adolescent girls and therefore most likely should not be considered in talent detection programs for sporting ability in girls.
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Krishan K, Kanchan T, Asha N, Kaur S, Chatterjee PM, Singh B. Estimation of sex from index and ring finger in a North Indian population. J Forensic Leg Med 2013; 20:471-9. [PMID: 23756517 DOI: 10.1016/j.jflm.2013.03.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 12/18/2012] [Accepted: 03/02/2013] [Indexed: 11/19/2022]
Abstract
Estimation of sex is an important parameter in the examination of unknown dismembered and commingled remains. The present study explores the possibility of estimation of sex from length of index and ring finger and the index and ring finger ratio in 140 individuals (70 boys and 70 girls) from North India. Index finger length (IFL) and ring finger length (RFL) of the participants were measured following standard procedures and landmarks. Sex differentiation in the present study was based on sectioning point analysis. The 'sectioning point' for the IFL, RFL and the index and the ring finger ratio was estimated from the average of the mean of male and female values. Binary logistic regression (BLR) analysis was employed to derive a predicting equation for estimation of sex. The results of the present study indicate that significant sex differences exist in the IFL and RFL and index and ring finger ratio. Among finger lengths, RFL is a better predictor of sex than IFL. It is further concluded that the index and ring finger length is of limited utility in estimation of sex in forensic casework and should be employed only in cases when no other means of sexing are available. The study suggests that the index and ring finger ratio should not be employed in estimation of sex in forensic casework due to considerable overlap in male and female values.
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Affiliation(s)
- Kewal Krishan
- Department of Anthropology, Panjab University, Chandigarh, India.
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Sigurjonsdottir K, Bjorgulfsson TM, Aspelund T, Eiriksdottir G, Sigurdsson S, Ingvarsson T, Harris TB, Launer L, Gudnason V, Jonsson H. Type 3 finger length pattern is associated with total knee replacements due to osteoarthritis but not with hip replacements or hand osteoarthritis in the elderly: the AGES-Reykjavik study. BMC Musculoskelet Disord 2013; 14:112. [PMID: 23530906 PMCID: PMC3626925 DOI: 10.1186/1471-2474-14-112] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 03/13/2013] [Indexed: 11/10/2022] Open
Abstract
Background Recent case–control studies have shown an association between type 3 finger length pattern (longer ring finger than index finger) and knee osteoarthritis. This large cross-sectional study tests the hypothesis that the type 3 pattern is associated with total joint replacements due to osteoarthritis in a large population based study. Methods Finger length ratios were assessed visually on 5170 hand photographs (2975 females, 2195 males, mean age 76). In this population-based multidisciplinary study of aging in Reykjavik, Iceland, the prevalence of osteoarthritis associated total knee replacements was 223(4.3%) and total hip replacements 316(6.1%). We then performed a binary logistic regression analysis for total knee replacements and total hip replacements, including finger length patterns, osteoarthritis at other sites and other variables with possible association to osteoarthritis such as age, BMI and bone mineral density of the spine. Results The prevalence of the type 3 pattern was 50% (43% in females, 58% in males). The regression analysis revealed an odds ratio for total knee replacements of 1.65 (1.24-2.2) p = 0.0007, in the type 3 finger pattern group, similar in both genders. This association was independent of the associations we have previously reported between total knee replacements and BMI and the presence of hand osteoarthritis. No association was seen between finger length patterns and total hip replacements. Conclusion Finger length patterns read from digital photographs in this large study confirm previous radiographic observations with significant associations between the type 3 pattern and total knee replacements but not total hip replacements in both genders in this elderly group.
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Peeters MW, Claessens AL. Digit ratio (2D:4D) and competition level in world-class female gymnasts. J Sports Sci 2013; 31:1302-11. [PMID: 23506462 DOI: 10.1080/02640414.2013.779741] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In this study the relationship between the digit ratio (2D:4D) and artistic gymnastics performance and competition level was investigated in a sample of Caucasian world-class female gymnasts (n = 145). The sample was divided into three competition events (compulsories, free work, final score). Within each event three performance groups (lowest, middle, and highest) were based on the competition scores gathered at the World Championships at Rotterdam, the Netherlands, in 1987. Lengths of the digits were measured on X-rays of the left hand. Several anthropometric dimensions were measured and from those measurements an androgyny index (Bayer & Bayley) and somatotype components (endomorphy, mesomorphy, ectomorphy) were calculated. Although significant differences in some anthropometric characteristics between the performance level groups within each competition event were observed, no significant differences in the 2D:4D ratios were found between the performance level groups, varying from 0.918 ± 0.020 to 0.924 ± 0.020. Also, no significant correlations were observed between the 2D:4D ratio and anthropometric, androgyny, and somatotype characteristics, r varying from r = -0.11 to r = +0.12. It can be concluded that in this sample the 2D:4D digit ratio, unlike other anthropometric characteristics, is not a discriminating factor for the performance in artistic gymnastics performance on a world-class level.
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Kilduff L, Cook CJ, Bennett M, Crewther B, Bracken RM, Manning J. Right–left digit ratio (2D:4D) predicts free testosterone levels associated with a physical challenge. J Sports Sci 2013; 31:677-83. [DOI: 10.1080/02640414.2012.747690] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Hönekopp J. No Evidence that 2D:4D is Related to the Number of CAG Repeats in the Androgen Receptor Gene. Front Endocrinol (Lausanne) 2013; 4:185. [PMID: 24367354 PMCID: PMC3851970 DOI: 10.3389/fendo.2013.00185] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 11/13/2013] [Indexed: 11/13/2022] Open
Abstract
The length ratio of the second to the fourth digit (2D:4D) is a putative marker of prenatal testosterone (T) effects. The number of CAG repeats (CAGn) in the AR gene is negatively correlated with T sensitivity in vitro. Results regarding the relationship between 2D:4D and CAGn are mixed but have featured prominently in arguments for and against the validity of 2D:4D. Here, I present random-effects meta-analyses on 14 relevant samples with altogether 1904 subjects. Results were homogeneous across studies. Even liberal estimates (upper limit of the 95% CI) were close to zero and therefore suggested no substantial relationship of CAGn with either right-hand 2D:4D, left-hand 2D:4D, or the difference between the two. However, closer analysis of the effects of CAGn on T dependent gene activation in vitro and of relationships between CAGn and T dependent phenotypic characteristics suggest that normal variability of CAGn has mostly no, very small, or inconsistent effects. Therefore, the lack of a clear association between CAGn and 2D:4D has no negative implications for the latter's validity as a marker of prenatal T effects.
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Affiliation(s)
- Johannes Hönekopp
- Department of Psychology, Northumbria University , Newcastle upon Tyne , UK
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