Sport and training influence bone and body composition in women collegiate athletes

Muscle-to-bone and soft tissue-to-bone ratios in track and field athletes

The purpose of this study was to compare the muscle-to-bone (MBR) and soft tissue-to-bone ratios (SBR) of 459 track and field athletes across event groups to identify differences in MBR and SBR. Dual X-ray absorptiometry provided total and regional (i.e., arm, leg, trunk) lean mass (LM), fat mass (FM), and bone mineral content (BMC). MBR was calculated by dividing LM by BMC. The SBR was calculated by dividing LM+FM by BMC. Kruskal-Wallis tests were used to compare ratios across event groups. Dunn's post-hoc tests were utilized to adjust for multiple comparisons. Total MBR for females was higher in the throwers compared to the multievent athletes (p=0.02). For the males, total MBR was lower in jumpers compared to all events except pole vaulters (PV) (p<0.05). Trunk MBR was higher in the long-distance runners (LD) compared to jumpers, PV, and throwers (p<0.05). The throwers had higher total, arm, and leg SBRs compared to the jumpers, LD, middle distance, PV, and sprint groups (p<0.05). Significant differences in total and regional MBR and SBR were identified across event groups for both sexes, and may indicate event-specific adaptations impacting the balance between soft tissue and bone.

Healthy Eating Index and Dietary Inflammatory Index are not correlated with body composition in female collegiate athletes

OBJECTIVE

This cross-sectional study investigated associations among the Healthy Eating Index (HEI)-2015, Dietary Inflammatory Index (DII), and body composition in female collegiate athletes.

PARTICIPANTS

Female NCAA Division I student-athletes (n = 41, 18-21 years old) were included from various sports and did not report any diagnosed chronic diseases.

METHODS

Demographics, dietary intake, anthropometrics, and body composition, including bone mineral density, were collected utilizing a questionnaire, three interview-based multiple-pass 24-h dietary recalls, and dual-energy X-ray absorptiometry.

RESULTS

Mean HEI-2015 and DII scores (using 39 of 45 components) were 56.2 ± 13.5 and -0.1 ± 1.9, respectively. Athletes did not meet recommended intake levels for servings of fruit, vegetables, fiber, calcium, vitamin D, omega-3, and omega-6. Saturated fat and added sugar intake exceeded the recommended intakes. Diet quality indices and body composition measures were not correlated.

CONCLUSIONS

Although female collegiate athletes consumed poor-quality diets, this was not associated with body composition or bone health.

Endurance in Long-Distance Swimming and the Use of Nutritional Aids

BACKGROUND

Long-distance swimmers exert energetic, physiological, and neuromuscular demands that must be matched with adequate body composition to improve their performance in long-distance swimming.

OBJECTIVES

This review aims to compile all available information on energetic and physiological demands, optimal body composition, nutrition, and ergogenic supplements in long-distance swimming. This will provide an understanding of the specific challenges and needs of this sport and will help swimmers and coaches design more effective training and nutrition plans to optimise performance and achieve their goals.

METHODS

Databases such as Web of Science, SciELO Citation Index, MEDLINE (PubMed), Current Contents Connect, KCI-Korean Journal Database, and Scopus were searched for publications in English using keywords such as swimming, endurance, energy demands, physiological demands, nutrition, body composition, and ergogenic aids, individually or in combination.

RESULTS

There is convincing evidence that several physical indicators, such as propulsive surface area, technical, such as stroke rate, and functional, such as hydration strategies, are related to swimming performance and body composition. Each athlete may have a specific optimal body fat level that is associated with improved sporting performance. The nutritional needs of open water swimmers during competition are quite different from those of pool swimmers.

CONCLUSIONS

Swimmers with an adequate physique have a high body muscle mass and moderately related anaerobic strength both on land and in the water. These general and specific strength capacities, which are given by certain anthropometric and physiological characteristics, are seen throughout the work, as well as ergogenic and nutritional strategies, which have an important impact on long-distance swimming performance.

Physical Profiles of All-Rounders, Batters, and Bowlers in Sub-Elite Women's Cricket

ABSTRACT

Jacobs, J, Olivier, B, Brandt, C, and Jafta, G. Physical profiles of all-rounders, batters, and bowlers in sub-elite women's cricket. J Strength Cond Res 38(6): 1095-1102, 2024-The unique physical profile of each player's role in sub-elite women's cricket is vital for optimizing performance as these players progress to the elite levels. This quantitative, cross-sectional study investigates the physical profiles of sub-elite women's cricket players as a group and compares these profiles across different player roles. Sub-elite female cricket players in the South African domestic women's cricket league were included in this study. A battery of physical assessments were conducted at the start of the 2022/23 season. The physical assessments included body composition, individual muscle strength testing using dynamometry, 2-km time trial (TT), countermovement jump (CMJ), single-leg jump (SLJ), isometric mid-thigh pull, push-up, and hop test on force plates. A total of 44 female players (20.86 ± 1.6 years) were included in the study. Differences were found in muscle mass (p = 0.004) and peak power (p = 0.040) for all-rounders and bowlers. Player roles presented with different dominant (p = 0.006) and non-dominant (p = 0.066) knee flexion strength. The bowlers' body composition and physical strength profile are compromised compared with batters and all-rounders. There were several physical strength and power differences between pace and spin bowlers in CMJ and SLJ tests for jump height (p = 0.009) and peak power (p = 0.006). Batters performed the best in the 2-km TT. Body composition and musculoskeletal profiles for each player role can be baseline markers in sub-elite women's cricket. Stakeholders can use this information to guide physical preparation for players advancing to elite levels.

Off- to in-season body composition adaptations in elite male and female endurance and power event athletics competitors: an observational study

BACKGROUND

Monitoring elite athletes' body composition (BC) is vital for health and optimizing performance in sports emphasizing leanness, such as athletics. This study aims to investigate and compare sex- and event-specific off-to in-season BC changes in endurance and power event athletics competitors.

METHODS

Elite male and female endurance athletes (> 800 m runners; n = 21) and power event athletes (sprinters, jumpers; n = 32) underwent dual-energy X-ray absorptiometry (DXA) scans for whole and regional lean mass (LM), fat mass (FM), bone mineral content (BMC), and density (BMD) during off-season (September-October) and in-season (April-May). Linear mixed models tested between-group off-season differences in BC, within-group off-season to in-season changes, and between-group differences in change. To assess meaningful or least significant changes (LSC) in BC, DXA precision errors were determined from two consecutive total body scans in a subsample of athletes (n = 30).

RESULTS

Male athletes (n = 26) gained significantly (p < 0.05) more body mass (BM; mean difference 1.5 [95% confidence interval (CI):0.5-2.4] kg), LM (843 [95% CI:-253:1459] g), and trunk LM (756 [-502:1156] g) than female athletes (n = 27). The proportion of changes in athlete's BC exceeding the LSC threshold for LM and trunk LM were 70% and 65% in males, and 48% and 26% in females. Significant (p < 0.05) within-group off-season to in-season increases in LM were found for male endurance and power athletes, and female power athletes. All groups significantly increased BMD (p < 0.05). Only male and female power athletes had significant in- to-off-season increases in BMC. 80% of all athletes who had a meaningful increase in BMC belonged to the power event group. No significant within- or between group change in FM was observed.

CONCLUSIONS

The present study found that male athletes gained more BM, LM and trunk LM than females. Within-group increases in regional and whole-body LM and BMC were predominantly found among power event competitors. Incorporating individual meaningful changes alongside traditional statistics provided additional insights into sex and event-group differences. Future research on elite athletic event groups should include DXA measurements closer to major outdoor-season competitions, coupled with site-specific measures (ultrasound, MRI) for better detection of subtle changes in LM and FM.

Body fat of competitive volleyball players: a systematic review with meta-analysis

BACKGROUND

Reference values of body fat for competitive volleyball players are lacking, making it difficult to interpret measurement results. This review systematically summarized published data on the relative body fat of volleyball players and calculated potential differences between sex, measurement method, and competitive level.

METHODS

The protocol followed the Preferred Reported Items for Systematic Reviews and Meta-Analysis guidelines. The literature search was conducted using five electronic databases to retrieve all relevant publications from January 1, 2010, to July 1, 2021. The 63 studies including 2607 players that met the inclusion criteria were analyzed using random-effects models. Data were reported as pooled mean body fat with 95% confidence intervals.

RESULTS

Body fat for males and females was 12.8% (11.9-13.8%) and 22.8% (21.9-23.7%), respectively. Body fat was 18.3% (16.3-20.4%) measured via skinfolds, 18.4% (15.6-21.2%) via bioelectrical impedance analysis, 24.2% (20.4-28.0%) via dual-energy x-ray absorptiometry and 21.6% (17.4-25.8%) via densitometry. Regional, national, and international-level players had body fat values of 19.5% (17.8-21.2%), 20.3% (18.6-22.0%), and 17.9% (15.7-20.4%), respectively. When the meta-regression was adjusted for the variables sex, measurement method, and competitive level, a significant difference between sex (p < 0.001), dual-energy x-ray absorptiometry and skinfolds (p = 0.02), and national and international-level players (p = 0.02) was found. However, sensitivity analysis revealed that findings regarding measurement method and competitive level were not robust and should, therefore, be interpreted with caution.

CONCLUSIONS

Despite the limitations of published data, this meta-analysis provided pooled values for body fat of male and female volleyball players for different competitive levels and measurement methods.

Playing basketball and volleyball during adolescence is associated with higher bone mineral density in old age: the Bunkyo Health Study

Introduction: Exercise is beneficial for increasing areal bone mineral density (aBMD) in adolescence and maintaining it in old age. Moreover, high-impact sports are more effective than low-impact sports in increasing aBMD. This study aimed to determine the types of adolescent sports played in school-based sports clubs associated with aBMD in old age. Methods: In total, 1,596 older adults (681 men and 915 women, age: 65-84 years) living in an urban area of Japan were evaluated for the femoral neck and lumbar spine aBMD using dual-energy X-ray absorptiometry. The association between adolescent sports played in sports clubs and aBMD in old age was analyzed using multiple regression analysis, with femoral neck and lumbar spine aBMD as dependent variables, and sports type and participant characteristics such as age, body weight, and serum 25-hydroxyvitamin D [25(OH)D] level, as independent variables. Results: For the femoral neck, basketball was associated with aBMD in older men (β = 0.079, p < 0.05) and women (β = 0.08, p < 0.01), whereas current body weight and 25(OH)D level were associated with aBMD in both sexes. For the lumbar spine, volleyball (β = 0.08, p < 0.01) and swimming (β = 0.06, p < 0.05) was significantly associated with lumbar spine aBMD, whereas current body weight, 25(OH)D, and diabetes mellitus were associated with aBMD in older women. Conclusion: Both men and women who played basketball in adolescence had higher femoral neck aBMD in old age. Moreover, women who played volleyball in adolescence had higher lumbar spine aBMD in old age.

Bone Tissue Responsiveness To Mechanical Loading-Possible Long-Term Implications of Swimming on Bone Health and Bone Development

PURPOSE OF REVIEW

To revisit the bone tissue mechanotransduction mechanisms behind the bone tissue response to mechanical loading and, within this context, explore the possible negative influence of regular swimming practice on bone health, particularly during the growth and development period.

RECENT FINDINGS

Bone is a dynamic tissue, responsive to mechanical loading and unloading, being these adaptative responses more intense during the growth and development period. Cross-sectional studies usually report a lower bone mass in swimmers compared to athletes engaged in weigh-bearing sports. However, studies with animal models show contradictory findings about the effect of swimming on bone health, highlighting the need for longitudinal studies. Due to its microgravity characteristics, swimming seems to impair bone mass, but mostly at the lower limbs. It is unkown if there is a causal relationship between swimming and low BMD or if other confounding factors, such as a natural selection whithin the sport, are the cause.

Assessing Dietary Nutrient Adequacy and the Effect of Season-Long Training on Body Composition and Metabolic Rate in Collegiate Male Basketball Players

The success of performance in basketball relies on both optimal body composition and nutrient intake. The purpose of this study was to examine seasonal changes in body composition (BC), resting metabolic rate (RMR) and respiratory quotient (RQ), as well as dietary intake of National Collegiate Athletic Association (NCAA) Division I (DI) male basketball players. BC, RMR and RQ were assessed during pre-season, in-season, and post-season (September, December, and March) while dietary assessment data were collected in September and February. Results of this study indicated that players received inadequate energy (p < 0.0001), protein (p < 0.001) and carbohydrate (p < 0.0001) relative to the recommendations for exercising individuals during the September baseline period. However, following diet analysis and consultations and relative to recommendations, athletes received adequate amounts of energy and protein during follow-up, yet intakes of carbohydrate (p = 0.0025) were still significantly different than recommended. Results also indicated that there was a decrease in percent body fat (%BF) during season, an increase in lean body mass (LBM) from pre- to post-season, a peak in RMR during season and an increase in RQ post-season. These findings reveal that significant metabolic and body composition changes occur in players over the season and suggest that nutritional strategies employed concomitantly may be beneficial.

Regional Lean Soft Tissue and Intracellular Water Are Associated with Changes in Lower-Body Neuromuscular Performance: A Pilot Study in Elite Soccer Players

The assessment of body composition over a competitive season provides valuable information that can help sports professionals to evaluate the efficacy of training and nutritional strategies, as well as monitoring athletes’ health status. The purpose of this study was to examine the association of changes in body composition and hydration status with changes in lower-body neuromuscular performance in soccer. Twenty-two male professional soccer players (mean ± SD; age: 26.4 ± 4.8 years; height: 184.3 ± 5.7 cm; body mass: 81.1 ± 6.5 kg; body fat: 11.6 ± 1.5%) took part in the study, for which they were tested at the initial and final stage of the competitive season. Total (whole body) and regional (arms and legs) lean soft tissue (LST) were estimated to obtain the body composition profile. Total body water (TBW) content, including extracellular (ECW) and intracellular (ICW) water, was obtained to monitor players’ hydration status. Countermovement jump (CMJ) height, power, and strength were used to derive players’ lower-body neuromuscular performance. The results showed that changes in legs LST and ICW significantly (p < 0.01) explained (r2 = 0.39) the improvements in CMJ height, power, and strength from the initial to the final stage of the season. Given the high demand imposed on the lower limbs during a soccer season, being more susceptible to change compared to whole-body LST, assessing regional LST and ICW would be more appropriate to provide extended information on players’ readiness.

The Effect of Professional Sports Participation on Bone Content and Density in Elite Female Athletes

Background: The role of exercise in osteoporosis prevention has been proven. Nevertheless, there is no consensus about the types of sports, especially at professional levels. Non-impact sports such as swimming may have a negative effect or no effect. Objectives: Thus, the present study aimed to compare the effect of different sports on bone mineral content (BMC) and bone mineral density (BMD) of elite female athletes. Methods: This was a cross-sectional study consisting of 48 athletes in five groups of long-distance running, volleyball, basketball, swimming (n = 12 for each), and ten control subjects. For measuring the lumbar spine (L2 - L4) and proximal femur (femoral neck, trochanter, and Ward’s triangle), the dual-energy X-ray absorptiometry (DEXA) method was applied. Results: Indicated that the running, basketball, and volleyball groups had a significantly higher lumbar spine and proximal femur BMD than the swimming and control groups (P < 0.05). Running resulted in significantly higher lumbar spine BMC compared to volleyball, basketball, swimming, and control groups, respectively (P < 0.01), while basketball had higher proximal femur BMC than running and controls (P < 0.01). The Z-score of the lumbar spine in the running was significantly higher than in basketball, swimming, and controls (P < 0.05), while basketball had a significantly higher femur neck Z-score than volleyball, running, and controls (P < 0.001). Finally, the swimmers had significantly higher Z-scores in the lumbar and the proximal femur than non-athletes (P < 0.001). Conclusions: Although all sports are effective for improving the bone health, the swimmers had much better bone status than non-athletes, while the sports of long-distance running and basketball were more efficient than others; therefore, a combination of endurance and jumping exercises seems to be the best way to prevent osteoporosis.

Multidirectional basketball activities load different regions of the tibia: A subject-specific muscle-driven finite element study

The tibia is a common site for bone stress injuries, which are believed to develop from microdamage accumulation to repetitive sub-yield strains. There is a need to understand how the tibia is loaded in vivo to understand how bone stress injuries develop and design exercises to build a more robust bone. Here, we use subject-specific, muscle-driven, finite element simulations of 11 basketball players to calculate strain and strain rate distributions at the midshaft and distal tibia during six activities: walking, sprinting, lateral cut, jumping after landing, changing direction from forward-to-backward sprinting, and changing direction while side shuffling. Maximum compressive strains were at least double maximum tensile strains during the stance phase of all activities. Sprinting and lateral cut had the highest compressive (-2,862 ± 662 με and -2,697 ± 495 με, respectively) and tensile (973 ± 208 με and 942 ± 223 με, respectively) strains. These activities also had the highest strains rates (peak compressive strain rate = 64,602 ± 19,068 με/s and 37,961 ± 14,210 με/s, respectively). Compressive strains principally occurred in the posterior tibia for all activities; however, tensile strain location varied. Activities involving a change in direction increased tensile loads in the anterior tibia. These observations may guide preventative and management strategies for tibial bone stress injuries. In terms of prevention, the strain distributions suggest individuals should perform activities involving changes in direction during growth to adapt different parts of the tibia and develop a more fatigue resistant bone. In terms of management, the greater strain and strain rates during sprinting than jumping suggests jumping activities may be commenced earlier than full pace running. The greater anterior tensile strains during changes in direction suggest introduction of these types of activities should be delayed during recovery from an anterior tibial bone stress injury, which have a high-risk of healing complications.

Adolescent female handball players present greater bone mass content than soccer players: A cross-sectional study

BACKGROUND

Osteoporosis is a systemic disease affecting half of women over the age of 50 years. Considering that almost 90% of peak of bone mass is achieved until the second decade of life, ensuring a maximal bone mineral content acquisition may compensate for age-associated bone loss. Among several other factors, physical activity has been recommended to improve bone mass acquisition. However, it is unknown whether athletes involved with sports with different impact loading characteristics differ in regards to bone mass measurements.

AIM

To compare the bone mass content, bone mass density and lean mass of young female soccer players (odd-impact loading exercise), handball players (high-impact loading exercises) and non-athletes.

METHODS

A total of 115 female handball players (15.5 ± 1.3 years, 165.2 ± 5.6 cm and 61.9 ± 9.3 kg) and 142 soccer players (15.5 ± 1.5 years, 163.7 ± 6.6 cm and 56.5 ± 7.7 kg) were evaluated for body composition using a dual-emission X-ray absorptiometry system, and 136 female non-athletes (data from NHANES) (15.1 ± 1.32 years, 163.5 ± 5.8 cm and 67.2 ± 19.4 kg) were considered as the control.

RESULTS

Handball players presented higher bone mass content values than soccer players for upper limbs (294.8 ± 40.2 g and 270.7 ± 45.7 g, p < 0.001), lower limbs (1011.6 ± 145.5 g and 967.7 ± 144.3 g, p = 0.035), trunk (911.1 ± 182.5 g and 841.6 ± 163.7 g, p = 0.001), ribs (312.4 ± 69.9 g and 272.9 ± 58.0 g, p < 0.001), spine (245.1 ± 46.8 g and 222.0 ± 45.1 g, p < 0.001) and total bone mass (2708.7 ± 384.1 g and 2534.8 ± 386.0 g, p < 0.001). Moreover, non-athletes presented lower bone mass content for lower limbs (740.6 ± 132.3 g, p < 0.001), trunk (539.7 ± 98.6 g, p < 0.001), ribs (138.2 ± 29.9 g, p < 0.001), pelvis (238.9 ± 54.6 g, p < 0.001), spine (152.8 ± 26.4 g, p < 0.001) and total bone mass (1987.5 ± 311.3 g, p < 0.001) than both handball and soccer players. Handball players also presented higher bone mass density values than soccer players for trunk, ribs and spine (p < 0.05) and handball and soccer players presented higher bone mass density than non-athletes for all measurements (p < 0.005). Finally, the non-athletes' lower limb lean mass was lower than soccer and handball players values (p < 0.05).

CONCLUSION

Adolescent females engaged in handball training for at least one year present higher bone mass contents than those who are engaged in soccer training, which, in turn, present higher bone mass contents than non-athletes. These results might be used by physicians and healthcare providers to justify the choice of a particular sport to enhance bone mass gain in female adolescents.

"The Competitive Season and Off-Season": Preliminary Research concerning the Sport-Specific Performance, Stress, and Sleep in Elite Male Adolescent Basketball Athletes

BACKGROUND

Through scholastic sports programs, adolescent athletes compete to represent their communities. However, few studies investigate the changes in physiological and mental profiles during varied sport periodization among this population. Therefore, the purpose of this study was to compare the changes in sports performance and stress-related biomarkers between the competitive season (CS) and off-season (OS) in elite adolescent basketball players.

METHOD

Nine elite Division I male basketball players (age: 15-18 years. old) participated in this study. Basketball-specific performance, salivary dehydroepiandrosterone sulfate (DHEA-S)/cortisol levels, mood state, and sleep quality were all accessed during the CS and OS periods.

RESULTS

The training load during OS was 26.0% lower than CS (p = 0.001). Muscle mass, aerobic capacity, 10 m sprint, and Abalakov jump (AJ) power during OS were greater than that during CS (+2.2-9.8%, p < 0.05), but planned agility was greater during CS (p = 0.003). The salivary DHEA-S/cortisol was greater during CS than during OS (p = 0.039). The overall mood state and sleep quality did not differ between periods, but the POMS-tension was higher during CS (p = 0.005).

CONCLUSION

The present study demonstrates that muscle mass, aerobic capacity, peak AJ power, and 10 m sprint performance, but not planned agility, were greater during OS compared to CS among elite adolescent basketball players. Furthermore, the stress-related responses reflected by the D/C ratio and mood tension were relatively lower during the OS in these athletes. Thus, this study suggests that coaches and sport science professionals should closely monitor athletes' training states across varied training/competition periods to better react to modifying training or recovery plans.

COMPARISON OF BONE PARAMETERS BY BODY REGION IN UNIVERSITY ATHLETES: SYSTEMATIC REVIEW

ABSTRACT Introduction: Bone mineral density (BMD) and bone mineral content (BMC) vary depending on the type of sport practiced and the body region, and their measurement can be an effective way to predict health risks throughout an athlete’s life. Objective: To describe the methodological aspects (measurement of bone parameters, body regions, precision errors and covariates) and to compare BMD and BMC by body region (total body, upper limbs, lower limbs and trunk) among university athletes practicing different sports. Methods: A search was performed on the databases PubMed, Web of Science, Scopus, ScienceDirect, EBSCOhost, SportDiscus, LILACS and SciELO. Studies were selected that: (1) compared BMD and BMC of athletes practicing at least two different sports (2) used dual-energy X-ray absorptiometry (DXA) to assess bone parameters (3) focused on university athletes. The extracted data were: place of study, participant selection, participants’ sex, sport practiced, type of study, bone parameters, DXA model, software used, scan and body regions, precision error, precision protocol, covariates and comparison of bone parameters between different sports by body region. Results: The main results were: 1) BMD is the most investigated bone parameter; 2) total body, lumbar spine and proximal femur (mainly femoral neck) are the most studied body regions; 3) although not recommended, the coefficient of variation is the main indicator of precision error; 4) total body mass and height are the most commonly used covariates; 5) swimmers and runners have lower BMD and BMC values; and 6) it is speculated that basketball players and gymnasts have greater osteogenic potential. Conclusions: Swimmers and runners should include weight-bearing exercises in their training routines. In addition to body mass and height, other covariates are important. The results of this review can help guide intervention strategies focused on preventing diseases and health problems during and after the athletic career. Level of evidence II; Systematic Review.

The effect of impact exercise on bone mineral density: A longitudinal study on non-athlete adolescents

PURPOSE

High impact exercise is known to induce osteogenic effects in the skeleton. However, less is known about the systemic effect of exercise practice in a potential adaptive mechanism of the skeletal accrual. This research aimed to assess the effect of impact exercise on bone mineral density (BMD) in the radius throughout adolescence.

METHODS

This study evaluated 1137 adolescents, at 13 and 17 years old, as part of the population-based cohort EPITeen. BMD (g/cm²) was measured at the ultradistal and proximal radius of the non-dominant forearm by dual-energy X-ray absorptiometry (DXA) using a Lunar® Peripheral Instantaneous X-ray Image device. The practice of (extra-curricular) exercise was categorized as: no exercise, exercise with high impact and exercise with low impact. Regression coefficients (β) and respective 95% confidence intervals (CI_95%) were used to estimate the association between exercise practice categories at 13 years old and BMD at 13 and 17 years old and BMD gain between evaluations.

RESULTS

In boys, at 13 years, BMD was similar between the ones not practicing exercise and those practicing exercise with low impact, and the gain of BMD was also similar in both groups. Still in boys, at 13 years, those who practiced exercise with high impact presented higher mean (standard-deviation) of BMD, comparing to the other two groups (no exercise and low impact exercise), and also significantly increased the BMD gain between 13 and 17 years (β = 0.013; CI_95%0.003;0.023). In girls, no statistically significant differences on BMD were found between the categories of exercise at 13 years and BMD at 17 years of age.

CONCLUSION

This research shows that the practice of high impact exercise could help to increase BMD more than low impact exercise even in a nonweight-bearing bone during adolescence.

Body Composition Values of NCAA Division 1 Female Athletes Derived From Dual-Energy X-Ray Absorptiometry

ABSTRACT

Dobrosielski, DA, Leppert, KM, Knuth, ND, Wilder, JN, Kovacs, L, and Lisman, PJ. Body composition values of NCAA Division 1 female athletes derived from dual-energy x-ray absorptiometry. J Strength Cond Res 35(10): 2886-2893, 2021-This study generated descriptive data for regional and total body composition and bone mineral density (BMD) measures using dual-energy x-ray absorptiometry (DXA) across 12 NCAA Division 1 female competitive sports. Two hundred seventy-eight female collegiate athletes underwent DXA: basketball (BB; n = 28), cross country (CC = 11), field hockey (FH; n = 35), gymnastics (GYM; n = 23), lacrosse (LAX; n = 48), soccer (SOC; CC = 27), softball (SB; n = 24), swimming and diving (SW; n = 35), tennis (TN; n = 11), track and field ([TR-throw; n = 10]; [TR-run; n = 10]), and volleyball (VB; n = 16). Descriptive statistics for all body composition and BMD measures were calculated. Group mean differences in all regional and total body composition (all, p < 0.001; η2 range = 0.177-0.365) and BMD (all, p < 0.001; η2 range = 0.317-0.383) measures were observed between teams. The total BF% for gymnasts (23.5%) was lower than TN, FH, LAX, SB, and TR-throw (mean difference range: -4.6 to -12.9%, all p < 0.01); TR-throw had the highest total BF% (36.4%). Cross country had lower total BMD (1.17 g·cm-2) than FH, TR-throw, LAX, GYM, SOC, SB, VB, and BB (mean difference range: -0.12 to -0.26 g·cm-2, all p < 0.01); BB and TR-throw had the highest total BMD (1.40 and 1.43 g·cm-2, respectively). Our data confirm that regional and total body composition and BMD measures varied across female collegiate sports. These findings may assist sports medicine and strength and conditioning practitioners with identifying sport-specific goal values for BF% and BMD to optimize program design.

New Frontiers of Body Composition in Sport

The body composition phenotype of an athlete displays the complex interaction among genotype, physiological and metabolic demands of a sport, diet, and physical training. Observational studies dominate the literature and describe the sport-specific physique characteristics (size, shape, and composition) of adult athletes by gender and levels of competition. Limited data reveal how body composition measurements can benefit an athlete. Thus, the objective is to identify purposeful measurements of body composition, notably fat and lean muscle masses, and determine their impact on the health and performance of athletes. Areas of interest include relationships among total and regional body composition measurements, muscle function, sport-specific performance, risk of injury, return to sport after injury, and identification of activity-induced fluid shifts. Discussion includes the application of specific uses of dual X-ray absorptiometry and bioelectrical impedance including an emphasis on the need to minimize measurement errors and standardize protocols, and highlights opportunities for future research. This focus on functional body composition can benefit the health and optimize the performance of an athlete.

Body Composition in International Sprint Swimmers: Are There Any Relations with Performance?

The paper addresses relations between the characteristics of body composition in international sprint swimmers and sprint performance. The research included 82 swimmers of international level (N = 46 male and N = 36 female athletes) from 8 countries. We measured body composition using multifrequency bioelectrical impedance methods with “InBody 720” device. In the case of male swimmers, it was established that the most important statistically significant correlation with sprint performance is seen in variables, which define the quantitative relationship between their fat and muscle with the contractile potential of the body (Protein-Fat Index, r = 0.392, p = 0.007; Index of Body Composition, r = 0.392, p = 0.007; Percent of Skeletal Muscle Mass, r = 0.392, p = 0.016). In the case of female athletes, statistically significant relations with sprint performance were established for variables that define the absolute and relative amount of a contractile component in the body, but also with the variables that define the structure of body fat characteristics (Percent of Skeletal Muscle Mass, r = 0.732, p = 0.000; Free Fat Mass, r = 0.702, p = 0.000; Fat Mass Index, r = −0.642, p = 0.000; Percent of Body Fat, r = −0.621, p = 0.000). Using Multiple Regression Analysis, we managed to predict swimming performance of sprint swimmers with the help of body composition variables, where the models defined explained 35.1 and 75.1% of the mutual variability of performance, for male and female swimmers, respectively. This data clearly demonstrate the importance of body composition control in sprint swimmers as a valuable method for monitoring the efficiency of body adaptation to training process in order to optimize competitive performance.

Positional Body Composition of Female Division I Collegiate Volleyball Players

Bisch, KL, Bosch, TA, Carbuhn, A, Stanforth, PR, Oliver, JM, Bach, CW, and Dengel, DR. Positional body composition of female division I collegiate volleyball players. J Strength Cond Res 34(11): 3055-3061, 2020-The primary study objective was to measure positional differences in total and regional body composition among female NCAA Division I collegiate volleyball players using dual X-ray absorptiometry (DXA). The secondary objective was to examine normative age curves for fat and lean mass (LM) variables. Ninety female volleyball players from 5 universities received a DXA scan. Athletes were categorized by position: middle blocker (MB = 31), outside hitter (OH = 32), setter (ST = 9), and Libero (LB = 18). Height, body mass, total and regional fat mass (FM), LM, bone mineral density (BMD), and abdominal visceral adipose tissue were measured by DXA. Body mass distribution ratios were calculated. The secondary age analysis included a subset of 153 DXA scans (n = 83, ages 18-21 years). Front row players (i.e., MB and OH) had significantly greater total and regional LM and BMD measures (p < 0.05, all), compared with non-front row players (i.e., LB and ST). Differences in total LM (p < 0.001) were significantly influenced by height. Front row players had consistently lower mass distribution ratios compared with non-front row players (p < 0.05, all). Lean mass index (LMI, p = 0.752) and FM index (FMI, p = 0.392) were not significantly different across ages. Back row players have greater relative upper body mass, whereas mass in front row players is more evenly distributed between the upper and lower body. Bone mineral density differences may be influenced by repeated impact of jumping during the attacking and blocking actions of front row players. Minimal changes in LMI and fluctuations in FMI can be expected across an athlete's career.

Basketball players possess a higher bone mineral density than matched non-athletes, swimming, soccer, and volleyball athletes: a systematic review and meta-analysis

Basketball athletes possess a higher bone mineral density (BMD) than matched non-athletes and swimming, soccer, and volleyball athletes. Differences appear to be exacerbated with continued training and competition beyond adolescence. The greater BMD in basketball athletes compared to non-athletes, swimming, and soccer athletes is more pronounced in males than females.

PURPOSE

The aim of this study was to examine differences in total and regional bone mineral density (BMD) between basketball athletes, non-athletes, and athletes competing in swimming, soccer, and volleyball, considering age and sex.

METHODS

PubMed, MEDLINE, ERIC, Google Scholar, and Science Direct were searched. Included studies consisted of basketball players and at least one group of non-athletes, swimming, soccer, or volleyball athletes. BMD data were meta-analyzed. Cohen's d effect sizes [95% confidence intervals (CI)] were interpreted as: trivial ≤ 0.20, small = 0.20-0.59, moderate = 0.60-1.19, large = 1.20-1.99, and very large ≥ 2.00.

RESULTS

Basketball athletes exhibited significantly (p < 0.05) higher BMD compared to non-athletes (small-moderate effect in total-body: d = 1.06, CI 0.55, 1.56; spine: d = 0.67, CI 0.40, 0.93; lumbar spine: d = 0.96, CI 0.57, 1.35; upper limbs: d = 0.70, CI 0.29, 1.10; lower limbs: d = 1.14, CI 0.60, 1.68; pelvis: d = 1.16, CI 0.05, 2.26; trunk: d = 1.00, CI 0.65, 1.35; and femoral neck: d = 0.57, CI 0.16, 0.99), swimming athletes (moderate-very large effect in total-body: d = 1.33, CI 0.59, 2.08; spine: d = 1.04, CI 0.60, 1.48; upper limbs: d = 1.19, CI 0.16, 2.22; lower limbs: d = 2.76, CI 1.45, 4.06; pelvis d = 1.72, CI 0.63, 2.81; and trunk: d = 1.61, CI 1.19, 2.04), soccer athletes (small effect in total-body: d = 0.58, CI 0.18, 0.97), and volleyball athletes (small effect in total-body: d = 0.32, CI 0.00, 0.65; and pelvis: d = 0.48, CI 0.07, 0.88). Differences in total and regional BMD between groups increased with age and appeared greater in males than in females.

CONCLUSION

Basketball athletes exhibit a greater BMD compared to non-athletes, as well as athletes involved in swimming, soccer, and volleyball.

Bone Mineral Reference Values for Athletes 11 to 20 Years of Age

Objectives. Training for sport is associated with the development of bone minerals, and the need for reference data based on athletes is often indicated. The purpose of this study was to develop a reference for bone mineral density (BMD) and content (BMC) specific for youth athletes of both sexes participating in several sports. Methods DEXA (dual energy X-ray absorptiometry) was used for total body measurements of bone minerals in 1385 athletes 11 to 20 years, 1019 males and 366 females. The athletes were training in several sports at Hungarian academies. Reference values for total bone mineral density and bone mineral content, and also BMD excluding the head (total body less head, TBLH) were developed using the LMS chartmaker pro version 2.3. Results. The centile distributions for BMD and BMC of the athletes differed significantly from those of the age- and sex-specific references for the general population. The youth athletes had higher BMD and BMC than those of the reference for the general population. Conclusion. The potential utility of the DEXA reference for male and female youth athletes may assist in monitoring changes in the BMC and BMD associated with normal growth and maturation, and perhaps more importantly, may be useful in monitoring changes specific to different phases of sport-specific training protocols.

Body Composition and Bone Mineral Density of Division 1 Collegiate Track and Field Athletes, a Consortium of College Athlete Research (C-CAR) Study

The purpose of the present study was to generate normative values for total and regional body composition in male and female Division 1 collegiate track and field athletes using dual X-ray absorptiometry. We also sought to examine body composition by event and sex. Data were used from the Consortium of College Athlete Research group. A total of 590 (male [M]/female [F] = 274/316) athletes had their height, weight, total and regional fat mass (FM), lean mass, and bone mineral density (BMD) measured. Athletes were classified into 1 of 7 categories: Jumps (M/F = 28/30); Long Distance (M/F = 104/110), Middle Distance (M/F = 27/24), Multievent (M/F = 11/9), Pole Vault (M/F = 21/27), Sprints (M/F = 54/96), and Throws (M/F = 29/20). Total and regional differences between events and sex were assessed by analysis of variance. Except for male and female throwers, all other track and field athletes' mean percent body fat (M: 10.3%-12.6%, F: 17.5%-21.6%) and visceral FM (<500 g) was low, but in a healthy range. As expected, throwers had significantly (p < 0.05) higher total and regional FM and lean mass than other events. In addition, male (1.55 ± 0.11 g/cm²) and female (1.40 ± 0.12 g/cm²) throwers had significantly greater BMD than all other events while male (1.25 ± 0.10 g/cm²) and female (1.16 ± 0.09 g/cm²) distance runners had significantly lower BMD than all other events. In conclusion, track athletes' body composition differed across events for both males and females. These measurements provide normative data on NCAA Division 1 male and female track and field athletes.

Changes in Triathletes' Performance and Body Composition During a Specific Training Period for a Half-Ironman Race

The number of recreational athletes completing a Half-Ironman triathlon has increased exponentially in recent years. However, there is a lack of research on how to train for this kind of an event. The purpose of this study was thus to analyse triathletes’ changes in performance and body composition following a triathlon-specific training period. Fourteen male amateur triathletes completed a 7-week period of general training and a 13-week period of specific training for a Half-Ironman triathlon. Anthropometric measures and performance tests were carried out to assess the effects of the specific training program. Results showed that the pre-test value of VO_2max for cycling was inversely correlated not only with the percentage of change in cycling performance, but also with the percentage change in several variables of running performance. In swimming, inverse correlations were observed between the time of the first 800 m test and the time percentage change for this test, but not with the percentage change in the performance of other segments of the race. Moreover, the somatotype component of endomorphy and the fat mass percentage of the first anthropometry were highly correlated with the percentage change in VO_2max in the run segment. These results highlight the importance of providing individualised training, considering that the same training program had a different impact on recreational triathletes belonging to the same group. Amateur athletes with higher initial performance levels probably need a greater amount of training to achieve improved adaptation.

Dual-Energy X-Ray Absorptiometry Body Composition in NCAA Division I Athletes: Exploration of Mass Distribution

BACKGROUND

Body composition assessment is frequently used in sports medicine and athletic performance environments to assess change in response to strength training and nutrition programs. However, to effectively do so requires knowledge regarding expected body composition values relative to sport and sex. Dual-energy x-ray absorptiometry (DXA) is widely used to evaluate body composition, although its utility in relationship to specific sports, performance, or rehabilitation is not clearly defined.

HYPOTHESIS

Body composition metrics and distribution of National Collegiate Athletic Association Division I collegiate athletes will vary based on sport and sex.

LEVEL OF EVIDENCE

Level 4.

STUDY DESIGN

Cross-sectional study.

METHODS

A convenience sample of 337 athletes (229 men and 108 women) participating in football, wrestling, soccer, hockey, basketball, golf, softball, or volleyball was evaluated. DXA-measured total body composition, including bone mineral density (BMD), % lean mass, % fat, and regional distribution, were compared by sex, sport, and with an age-matched National Health and Nutrition Examination Survey (NHANES) population.

RESULTS

Men had higher BMD, lower % fat (16.4% vs 25.2%) and higher % lean mass (79.2% vs 70.6%) (P < 0.001). Regional composition varied by sport and sex, with women having a greater proportion of lean mass at the trunk and men in their arms (P < 0.0001). Leg lean mass was distributed similarly between sexes (35%). Overall, the normative group (NHANES) had lower BMD and higher percentage fat.

CONCLUSION

DXA-measured body composition and lean mass distribution varies by sport and sex in Division I athletes. The observed difference to the NHANES population emphasizes challenges in identifying appropriate comparison populations, reinforcing the need to compare athletes with their own baseline.

CLINICAL RELEVANCE

These findings establish a framework to investigate the relevance of these variances and determine the utility of body composition analysis in elite athletes.

Whole-body dual-energy X-ray absorptiometry demonstrates better reliability than segmental body composition analysis in college-aged students

Dual-energy X-ray absorptiometry (DXA) is rapidly becoming more accessible and popular as a technique to monitor body composition. The reliability of DXA has been examined extensively using a number of different methodological approaches. This study sets up to investigate the accuracy of measuring the parameters of body composition (BC) by means of the whole-body and the segmental DXA method analysis with the typical error of measurement (TEM) that allows for expressing the error in the units of measure. The research was implemented in a group of 63 participants, all of whom were university students. Thirty-eight males (22.6±2.9 years, average body mass 77.5±8.4 kg) and 25 females (21.4±2.0 years, average body mass 58.6±7.2 kg) were recruited. The measured parameters included body mass (BM), fat-free mass (FFM), body fat (BF), bone mineral content (BMC), bone mineral density (BMD). For the whole-body analysis, the determined TEM was: BM at the level of 0.12 kg in females and 0.29 kg in males; BF 0.25kg and 0.44% females, 0.52 kg and 0.66% males; FFM 0.24 kg females and 0.42 kg males; BMC 0.02 kg females and males; BMD 0.01g/cm2 females and males. The TEM values in the segmental analysis were: BF within the range of 0.04-0.28 kg and 0.68-1.20% in females, 0.10-0.36 kg and 0.72-1.94% in males; FFM 0.08-0.41 kg females and 0.17-0.86 males, BMC 0.00-0.02 kg females and 0.01-0.02 kg males in relation to the body segment (upper limb, trunk, lower limb). The BMD value was at the level of 0.01-0.02g/cm2. The study results showed high reliability in measuring body composition parameters using the DXA method. The whole-body analysis showed a higher accuracy of measurement than the segmental. Only the changes that are greater than the TEM, or the upper bound (95%) of the confidence interval of the measurement can be considered demonstrable when interpreting repeated measurements.

Normative fat-free mass index values for a diverse sample of collegiate female athletes

The purpose of this study was to establish normative fat-free mass index (FFMI) ranges in collegiate female athletes. A sample of 266 female athletes (Mean±SD; Age: 19.7 ± 1.5 yrs, Height: 166.0 ± 6.4 cm, Weight: 63.2 ± 8.8 kg) were included in analyses. Dual-energy X-ray absorptiometry measured bone mineral content (BMC; kg) and lean mass (LM; kg). Fat-free mass index was calculated as follows: FFMI = (BMC + LM)/Height². Participants were classified by sport: cross-country (XC), field hockey, football, gymnastics, lacrosse, resistance-trained, swimming track. Mean, range and percentile ranks of FFMI were calculated for the full sample for each cohort. For all females, mean FFMI was 16.9 ± 1.7 kg/m², FFMI values ranged from 13.3 to 25.5 kg/m². The XC athletes had the lowest FFMI (15.3 ± 0.96 kg/m²; p < 0.001). Mean FFMI measures were similar between all other female athletes. Percentile ranks varied across sport; median FFMI was highest for football (18.0 kg/m²), lowest for XC (15.1 kg/m²) and ranged between 16.4 and 17.3 kg/m² for all other athletes. Establishing sport-specific FFMI values for female athletes may be beneficial for athletes and coaches by leading to more appropriate body composition goals based on FFM.

Seasonal and Longitudinal Changes in Body Composition by Sport-Position in NCAA Division I Basketball Athletes

The purpose of this study was to assess the body composition of male and female basketball athletes (n = 323) across season, year, and sport-position using air displacement plethysmography. An independent sample t-test assessed sport-position differences. An analysis of variance was used to assess within-subjects across season (pre-season, in-season, and off-season), and academic year (freshman, sophomore, and junior). For both men and women basketball (MBB, WBB) athletes, guards had the lowest body fat, fat mass, fat free mass, and body mass. No seasonal differences were observed in MBB, but following in-season play for WBB, a reduction of (p = 0.03) in fat free mass (FFM) was observed. Across years, MBB showed an increase in FFM from freshman to sophomore year, yet remained unchanged through junior year. For WBB across years, no differences occurred for body mass (BM), body fat (BF%), and fat mass (FM), yet FFM increased from sophomore to junior year (p = 0.009). Sport-position differences exist in MBB and WBB: Guards were found to be smaller and leaner than forwards. Due to the importance of body composition (BC) on athletic performance, along with seasonal and longitudinal shifts in BC, strength and conditioning practitioners should periodically assess athletes BC to ensure preservation of FFM. Training and nutrition programming can then be adjusted in response to changes in BC.

Increased Leg Bone Mineral Density and Content During the Initial Years of College Sport

Scerpella, JJ, Buehring, B, Hetzel, SJ, and Heiderscheit, BC. Increased leg bone mineral density and content during the initial years of college sport. J Strength Cond Res 32(4): 1123-1130, 2018-Bone mineral density (BMD) and bone mineral content (BMC) data are useful parameters for evaluating how training practices promote bone health. We used dual-energy X-ray absorptiometry (DXA) to longitudinally assess sport-specific growth in leg and total body BMD/BMC over the initial 2 years of collegiate training. Eighty-five Division 1 collegiate basketball, hockey, and soccer athletes (50 males and 35 females; age 19.0 [0.8] years) underwent annual DXA scans. Leg and total body BMD/BMC were compared within and across two 1-year intervals (periods 1 and 2) using repeated-measures analysis of variance, adjusting for age, sex, race, and sport. Leg BMD, leg BMC, and total body BMC all increased over period 1 (0.05 g·cm [p = 0.001], 0.07 kg [p = 0.002], and 0.19 kg [p < 0.001] respectively). Changes in period 2 compared with period 1 were smaller for leg BMD (p = 0.001), leg BMC (p < 0.001), leg fat mass (p = 0.028), and total BMC (p = 0.005). Leg lean mass increased more during period 2 than period 1 (p = 0.018). Sports participation was the only significant predictor of change in leg BMD. Significant increases in both leg BMD and BMC were demonstrated over both 2-year periods, with greater gains during period 1. These gains highlight the importance of attentive training procedures, capitalizing on attendant physical benefits of increased BMD/BMC. Additional research in young adults, evaluating bone mass acquisition, will optimize performance and decrease risk of bone stress injury among collegiate athletes.

Energy Balance over One Athletic Season

INTRODUCTION

Magnitude and variation in energy balance (EB) components over an athletic season are largely unknown.

PURPOSE

We investigated the longitudinal changes in EB over one season and explored the association between EB variation and change in the main fat-free mass (FFM) components in highly trained athletes.

METHODS

Eighty athletes (54 males; handball, volleyball, basketball, triathlete, and swimming) were evaluated from the beginning of the season to the main competition stage. Resting and total energy expenditure (REE and TEE, respectively) were assessed by indirect calorimetry and doubly labeled water, respectively. Physical activity energy expenditure was calculated as TEE - 0.1 TEE - REE. Fat mass (FM), FFM, and bone mineral were evaluated with dual-energy x-ray absorptiometry; changed body energy stores were calculated as 1.0(ΔFFM/Δtime) + 9.5(ΔFM/Δtime). Total-body water (TBW) and its compartments were assessed through dilution techniques, and total-body protein was calculated from a four-compartment model, with body volume assessed by air displacement plethysmography.

RESULTS

Although a negative EB of -17.4 ± 72.7 kcal·d was observed (P < 0.05), EB varied widely among sports and across sex groups resulting in a net weight increase (0.7 ± 2.3 kg) that is attributable to significant changes in FFM (1.2 ± 1.6 kg) and FM (-0.7 ± 1.5 kg) (P < 0.05). EB was related with TBW and intracellular water (r = 0.354, r = 0.257, P < 0.05, respectively), regardless of sex, sports, and age.

CONCLUSIONS

The mean negative EB observed over the season resulted from the rate of FM use and FFM accretion, but with a large variation by sex and sports. TBW, but not total-body protein or mineral balance, explained the magnitude of EB, which means that athletes under a positive or a negative EB showed a TBW expansion or shrinkage, respectively, specifically within the cells, over one athletic season.

Swimming and peak bone mineral density: A systematic review and meta-analysis

This meta-analysis aims to determine the effects of regular swimming on bone mineral density (BMD) in young adults (18-30 years). A systematic search was performed in Pubmed, SPORTDiscus and the Cochrane Library from the earliest possible year to March 2016. Swimmers were compared to non-athletic controls (CG) and to high-impact athletes (HIGH). Effect sizes with the Hedges g in random effects models were developed. Fourteen studies met the inclusion criteria and were included in the meta-analyses. Swimmers presented similar BMD values to CG in whole-body (g = -0.20; P = 0.251), femoral neck (g = -0.05; P = 0.818) and lumbar spine (g = 0.18; P = 0.492); and lower BMD in the whole-body (g = -1.21; P < 0.001), femoral neck (g = -1.51; P < 0.001) and lumbar spine (g = -0.84; P = 0.017) than the HIGH. For the whole-body differences, the higher the latitude the smaller the differences between swimmers and HIGH (B = 0.10; P = 0.001). For the femoral neck differences, age also seemed to reduce the differences between groups (B = 0.19; P = 0.020). Young adult swimmers present similar BMD values than CG and lower values than HIGH.

Total Energy Expenditure, Energy Intake, and Body Composition in Endurance Athletes Across the Training Season: A Systematic Review

BACKGROUND

Endurance athletes perform periodized training in order to prepare for main competitions and maximize performance. However, the coupling between alterations of total energy expenditure (TEE), energy intake, and body composition during different seasonal training phases is unclear. So far, no systematic review has assessed fluctuations in TEE, energy intake, and/or body composition in endurance athletes across the training season. The purpose of this study was to (1) systematically analyze TEE, energy intake, and body composition in highly trained athletes of various endurance disciplines and of both sexes and (2) analyze fluctuations in these parameters across the training season.

METHODS

An electronic database search was conducted on the SPORTDiscus and MEDLINE (January 1990-31 January 2015) databases using a combination of relevant keywords. Two independent reviewers identified potentially relevant studies. Where a consensus was not reached, a third reviewer was consulted. Original research articles that examined TEE, energy intake, and/or body composition in 18-40-year-old endurance athletes and reported the seasonal training phases of data assessment were included in the review. Articles were excluded if body composition was assessed by skinfold measurements, TEE was assessed by questionnaires, or data could not be split between the sexes. Two reviewers assessed the quality of studies independently. Data on subject characteristics, TEE, energy intake, and/or body composition were extracted from the included studies. Subjects were categorized according to their sex and endurance discipline and each study allocated a weight within categories based on the number of subjects assessed. Extracted data were used to calculate weighted means and standard deviations for parameters of TEE, energy intake, and/or body composition.

RESULTS

From 3589 citations, 321 articles were identified as potentially relevant, with 82 meeting all of the inclusion criteria. TEE of endurance athletes was significantly higher during the competition phase than during the preparation phase (p < 0.001) and significantly higher than energy intake in both phases (p < 0.001). During the competition phase, both body mass and fat-free mass were significantly higher compared to other seasonal training phases (p < 0.05).

CONCLUSIONS

Limitations of the present study included insufficient data being available for all seasonal training phases and thus low explanatory power of single parameters. Additionally, the classification of the different seasonal training phases has to be discussed. Male and female endurance athletes show important training seasonal fluctuations in TEE, energy intake, and body composition. Therefore, dietary intake recommendations should take into consideration other factors including the actual training load, TEE, and body composition goals of the athlete.

Body Composition and Muscle Characteristics of Division I Track and Field Athletes

The purpose of this study was to evaluate event-specific body composition and muscle characteristics of track and field athletes and to assess body composition changes after 1 year. Sixty collegiate track and field athletes (mean ± SD; age = 19.2 ± 1.4 years, height = 174.6 ± 9.0 cm, and weight = 71.5 ± 12.5 kg) were stratified into 6 event groups. Total and regional body composition measurements were assessed using dual-energy x-ray absorptiometry. A panoramic scan of the vastus lateralis was taken with B-mode ultrasound to determine muscle cross-sectional area and echo intensity (EI). Body composition measurements were repeated a year later in a subset of returning athletes (n = 33). Throwers had significantly more absolute fat mass (FM; 21.6 ± 11.0 kg), total body mass (89.7 ± 17.4 kg), percent fat (23.6 ± 7.8), and trunk fat (9.4 ± 5.8 kg) than all other event groups (p ≤ 0.05). Throwers had the most absolute lean mass (LM; 64.2 ± 11.7 kg; p > 0.05), but relative to body mass had relatively less LM (0.72 ± 0.08 kg; p ≤ 0.05). Despite high FM, throwers had lower EI (63.4 ± 5.2 a.u). After 1 year, relative armLM increased slightly in all event groups (p ≤ 0.05). Evaluation of muscle characteristics in addition to total and regional body composition may be valuable for improving performance, injury prevention, and assessing health risks. With appropriate training, track and field athletes may be able to minimize losses in LM and gains in FM between seasons.

Seasonal Effects on Body Composition, Muscle Characteristics, and Performance of Collegiate Swimmers and Divers

CONTEXT

 Previous researchers have indicated the importance of body composition and muscle quality in athletic performance. However, body composition and muscle-quality measures in swimmers and divers over a training season have yet to be evaluated.

OBJECTIVE

 To identify changes in body composition and muscle characteristics over a competitive season and identify relationships between these variables and performance in National Collegiate Athletic Association Division I swimmers and divers.

DESIGN

 Cross-sectional study.

SETTING

 University laboratory.

PATIENTS OR OTHER PARTICIPANTS

 A total of 17 collegiate swimmers and divers (age = 18.6 ± 0.7 years, height = 175.8 ± 4.0 cm, body mass = 69.7 ± 7.0 kg).

MAIN OUTCOME MEASURE(S)

 At preseason and postseason, body composition in each participant was assessed using dual-energy x-ray absorptiometry. Echo intensity and muscle cross-sectional area were determined from an ultrasound panoramic scan of the vastus lateralis muscle. Race times were obtained from the university athletic Web site.

RESULTS

 Lean mass (P = .016), arm lean mass (P = .008), and muscle cross-sectional area (P = .03) were higher at postseason, whereas body fat percentage (P = .041) and echo intensity (P = .0007) were lower at postseason. Performance improved from preseason to postseason in all event groups (sprinters, distance swimmers, and divers; P < .05).

CONCLUSIONS

 Body composition and muscle characteristics improved through 1 training season, which may have implications for performance. Quantifying body composition and muscle characteristics may be beneficial for professionals who work with athletes in order to improve performance and prevent injury.

A review of the effect of swim training and nutrition on bone mineral density in female athletes

PURPOSE

The present paper reviews the physiological adaptation to swim training and dietary supplementation relating to bone mineral density (BMD) in female swimmers. Swim training still seems to have conflicting effects on bone health maintenance in athletes.

METHODS

This review article focuses on swim training combined with dietary supplementation with respect to BMD in female athletes.

RESULTS

Upon review of previous studies, it became obvious that the majority of studies did not collect physical activity data on the swimmers outside of their swimming activities. These activities may have some influence on the BMD of swimmers and therefore, future studies need to examine additional physical activity history data as well as swim training. This additional information may help to explain why swimmers' BMD tends to be lower than the BMD of control individuals in many studies. Moreover, dietary supplementation such as calcium, magnesium, and vitamin D also affect bone health in swimmers, and it is extremely important to evaluate BMD in the context of dietary supplementation.

CONCLUSION

A review of the literature suggests that exercise intervention studies, including longitudinal and randomized control trials, need to attempt to introduce various exercise programs to female swimmers in order to determine the optimal exercise prescription for bone health.

Swimming and cycling do not cause positive effects on bone mineral density: a systematic review

Osteoporosis is considered a common metabolic bone disease and its prevalence is increasing worldwide. In this context, physical activity has been used as a non-pharmacological tool for prevention and auxiliary treatment of this disease. The aim of this systematic review was to evaluate the effects of cycling and swimming practice on bone mineral density (BMD). This research was conducted in accordance with the recommendations outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The studies were consulted in the period from 2004 to 2014, through major electronic databases: PubMed(®), SciELO(®) and LILACS(®). Ten studies evaluated the effects of cycling on BMD, and the results showed that nine studies have linked the practice of professional cycling with low levels of BMD. Another 18 studies have reported that swimming has no positive effects on bone mass. We conclude that cycling and swimming do not cause positive effects on BMD; thus, these are not the most suitable exercises for prevention and treatment of osteoporosis.

Swimming and cycling do not cause positive effects on bone mineral density: a systematic review

Osteoporosis is considered a common metabolic bone disease and its prevalence is increasing worldwide. In this context, physical activity has been used as a non-pharmacological tool for prevention and auxiliary treatment of this disease. The aim of this systematic review was to evaluate the effects of cycling and swimming practice on bone mineral density (BMD). This research was conducted in accordance with the recommendations outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The studies were consulted in the period from 2004 to 2014, through major electronic databases: PubMed®, SciELO® and LILACS®. Ten studies evaluated the effects of cycling on BMD, and the results showed that nine studies have linked the practice of professional cycling with low levels of BMD. Another 18 studies have reported that swimming has no positive effects on bone mass. We conclude that cycling and swimming do not cause positive effects on BMD; thus, these are not the most suitable exercises for prevention and treatment of osteoporosis.

The effects of a reformer Pilates program on body composition and morphological characteristics in active women after a detraining period

The aim of this quasi-experimental pilot study was to explore the effects of a reformer Pilates program on the anthropometry, body composition, and somatotype of active adult women after a short non-exercise period. Twenty-eight women (mean age: 40.21 ± standard deviation of 8.12 years old) with one to three years of reformer Pilates experience participated in the study. The women participated in a reformer Pilates program for 16 weeks (one hour, twice per week) after 4 weeks of detraining (summer holidays) in 2012. The International Society for the Advancement of Kinanthropometry full profile was assessed before and after the intervention program. Significant decreases (p ≤ 0.05) from pre- to post-program were observed for triceps, iliac crest, supraspinale, abdominal, front thigh and medial calf skinfold thicknesses, six and eight skinfold thickness sums, forearm and ankle girths, waist/hip ratio, endomorphy, and fat mass. Significant increases (p ≤ .05) were observed for corrected arm, corrected calf girths, and muscle mass. Generally, women showed a mesomorphic endomorph (endomorphy predominant) and mesomorph-endomorph (endomorphy and mesomorphy predominant) in the pre- and posttests, respectively. In conclusion, the practice of reformer Pilates was associated with healthy changes in anthropometric parameters, body composition, and somatotype in Pilates-experienced women after 4 weeks of no physical exercise.

Body composition of elite female players in five different sports games

The goal of this study was to identify and compare body composition (BC) variables in elite female athletes (age ± years): volleyball (27.4 ± 4.1), softball (23.6 ± 4.9), basketball (25.9 ± 4.2), soccer (23.2 ± 4.2) and handball (24.0 ± 3.5) players. Fat-free mass (FFM), fat mass, percentage of fat mass (FMP), body cell mass (BCM), extracellular mass (ECM), their ratio, the percentage of BCM in FFM, the phase angle (α), and total body water, with a distinction between extracellular (ECW) and intracellular water, were measured using bioimpedance analysis. MANOVA showed significant differences in BC variables for athletes in different sports (F60.256 = 2.93, p < 0.01, η2 = 0.407). The results did not indicate any significant differences in FMP or α among the tested groups (p > 0.05). Significant changes in other BC variables were found in analyses when sport was used as an independent variable. Soccer players exhibited the most distinct BC, differing from players of other sports in 8 out of 10 variables. In contrast, the athletes with the most similar BC were volleyball and basketball players, who did not differ in any of the compared variables. Discriminant analysis revealed two significant functions (p < 0.01). The first discriminant function primarily represented differences based on the FFM proportion (volleyball, basketball vs. softball, soccer). The second discriminant function represented differences based on the ECW proportion (softball vs. soccer). Although all of the members of the studied groups competed at elite professional levels, significant differences in the selected BC variables were found. The results of the present study may serve as normative values for comparison or target values for training purposes.

Peak-bone-mass development in young adults: effects of study program related levels of occupational and leisure time physical activity and exercise. A prospective 5-year study

SUMMARY

Young adulthood is characterized by profound life-style changes. This study suggests that reduction of sport or exercise, induced by alteration of the occupational situation, negatively impacts generation/maintenance of peak bone mass. In order to compensate occupational-related reductions of physical activity, workplace exercise programs will be helpful.

INTRODUCTION

Only few studies have determined the effect of physical activity or physical exercise on bone mineral density (BMD) in the period of late skeletal maturation, i.e. around peak bone mass. The aim of this article was to determine the long-term effect of different levels of physical activity and exercise directly and indirectly derived by occupation during young adulthood.

METHODS

Sixty-one male and female dental students (DES) and 53 male and female sport students (SPS) 21±2 years old were accompanied over the course (4.8±0.5 years) of their study program. BMD at the lumbar spine (LS), hip, and whole body (WB) were determined using dual-energy X-ray absorptiometry.

RESULTS

Parameters of physical activity increased non-significantly in both groups with no relevant differences between the groups. Indices of exercise, however, increased significantly in the SPS group while a significant decrease was assessed for the DES group. Independent of gender, BMD of the SPS increased significantly (p≤0.007) at all skeletal sites (LS, 2.4±3.9%; hip, 1.6±3.5%; WB, 1.8±2.8%) while BMD of the DES remained unchanged at LS (-0.6±4.4%, p=0.432) and WB (0.5±1.9%, p=0.092) but decreased significantly at the hip (-1.9±4.3%, p=0.010). BMD-changes at LS, hip, and WB differ significantly between SPS and DES (p≤0.017). Results remained unchanged after adjusting for baseline BMD-values that differed (p=0.030 to p=0.082) in favor of the SPS group.

CONCLUSION

Changes of exercise levels directly or indirectly caused by occupational factors during young adulthood significantly affected generation and/or maintenance of peak bone mass. Compensatory exercise is thus highly relevant for bone health of young adults.

Body composition, hemodynamic, and biochemical parameters of young female normal-weight oligo-amenorrheic and eumenorrheic athletes and nonathletes

AIMS

Low-weight hypogonadal conditions such as anorexia nervosa are associated with marked changes in body composition, hemodynamic and hematological parameters, and liver enzymes. The impact of athletic activity in normal-weight adolescents with/without amenorrhea on these parameters has not been assessed. Our aim was to examine these parameters in normal-weight athletes and nonathletes and determine any associations with body composition, oligo-amenorrhea, and exercise intensity.

METHODS

We assessed vital signs, complete blood counts, liver enzymes, and regional body composition in 43 oligo-amenorrheic athletes (OAA), 24 eumenorrheic athletes (EA), and 23 nonathletes aged 14-21 years.

RESULTS

The BMI was lower in OAA than in EA. Systolic and pulse pressure and temperature were lowest in OAA. Blood counts did not differ among groups. Aspartate aminotransferase (AST) was higher in both groups of athletes, while alanine aminotransferase (ALT) was higher in OAA than in EA and nonathletes. Total and regional fat were lower in OAA than in other groups, and these factors were associated positively with heart rate and inversely with liver enzymes.

CONCLUSIONS

Athletic activity is associated with higher AST levels, whereas menstrual dysfunction is associated with lower total and regional fat and higher ALT levels. Higher liver enzymes are associated with reductions in total and regional fat.

Body composition changes among female NCAA division 1 athletes across the competitive season and over a multiyear time frame

Body composition can affect athletic performance. Numerous studies have documented changes in body composition in female collegiate athletes from pre- to postseason; however, longitudinal studies examining changes across years are scarce. Therefore, the primary purpose of this study was to assess longitudinal body composition changes among female collegiate athletes across 3 years. Two hundred twelve female athletes from basketball (BB; n = 38), soccer (SOC; n = 47), swimming (SW; n = 52), track (sprinters and jumpers; TR; n = 49), and volleyball (VB; n = 26) with an initial mean age of 19.2 ± 1.2 years, height of 172.4 ± 8.9 cm, and total mass of 66.9 ± 9.0 kg had body composition assessments using dual-energy x-ray absorptiometry pre- and postseason over 3 years. A restricted maximum-likelihood linear mixed model regression analysis examined body composition differences by sport and year. Changes (p < 0.05) over 3 years included the following: Lean mass increased in VB from year 1 to 2 (0.7 kg), year 2 to 3 (1.1 kg), and year 1 to 3 (1.8 kg) and in SW from year 1 to 3 (0.6 kg); and percent body fat (%BF) increased in BB from year 1 to 3 (1.7%). There were no changes in SOC or TR. These results indicate that during their college careers, female collegiate athletes can be expected to maintain their %BF and athletes in sports like SW and VB can anticipate an increase in lean mass, but the increases may be less than many athletes, coaches, and trainers envision.

Cross-calibration of a GE iDXA and Prodigy for total and regional body bone parameters: the importance of using cross-calibration equations for longitudinal monitoring after a system upgrade

We aimed to determine if cross-calibration equations could be applied to convert GE Lunar Prodigy total and regional bone measurements to the GE iDXA model to support longitudinal monitoring of subjects. The cross-calibration group comprised 63 adults (age 45.1 [12.8] yr; body mass index: 25.6 [3.7] kg/m(2)) and the validation group comprised 25 adults (age 40.5 [11.5] yr; body mass index: 25.7 [3.5] kg/m(2)). The parameters reported were total and regional bone mineral density (BMD), bone mineral content, and bone area. There were significant differences between densitometers for all anatomical regions and reported bone parameters (p < 0.0001); iDXA reported lower BMD than the Prodigy apart from the ribs. Linear regression indicated good agreement for all measurements. Bland-Altman analyses indicated significant bias for all measurements and that cross-calibration equations were required. The derived cross-calibration equations were effective in reducing differences between predicted and measured results for each parameter and at each region apart from leg BMD, where the difference remained significant (0.013 g/cm(2); p < 0.05). Our results indicate that cross-calibration is important to maintain comparability of total body-derived regional bone measurements between the Lunar Prodigy and iDXA.