Upper and lower thresholds of fat-free mass index in a large cohort of female collegiate athletes

Fat-Free Mass Index in a Large Sample of National Collegiate Athletic Association Men and Women Athletes From a Variety of Sports

ABSTRACT

Magee, MK, Fields, JB, Jagim, AR, and Jones, MT. Fat-free mass index in a large sample of National Collegiate Athletic Association men and women athletes from a variety of sports. J Strength Cond Res 38(2): 311-317, 2024-Fat-free mass index (FFMI) can be used to categorize fat-free mass (FFM) relative to height. Normative values have been established in a variety of sports, as has suggested lower and upper thresholds of FFMI. However, FFMI has not been reported in a large sample of athletes, representing both sexes and multiple sport types. The purpose of this study was to evaluate differences in FFMI and establish normative values across a large sample of collegiate sports. A total of 1,961 athletes (men: n = 596, 10 sports; women: n = 1,365, 8 sports) participated. Height and mass were measured using a stadiometer and calibrated digital scale, respectively. Fat-free mass was assessed with air displacement plethysmography and used to calculate FFMI. Kruskal-Wallis test and one-way analysis of variance evaluated differences in FFMI in women's and men's sports, respectively. When collapsed across sport type and stratified by sex, men had a higher FFMI (21.5 ± 1.9 kg·m -2 vs. 17.9 ± 1.8 kg·m -2 ; p < 0.001). Differences occurred in FFMI across sport. In women, basketball athletes had the highest FFMI (18.9 kg·m -2 ) and highest 99th percentile for FFMI, whereas rowers had the lowest (16.9 kg·m -2 ). In men, throwers had the highest FFMI (25.7 kg·m -2 ) and highest 99th percentile, whereas volleyball athletes had the lowest (19.9 kg·m -2 ). Differences in FFMI may be attributable to dietary habits and physiological demands of respective sports. These results can provide information relative to differences in FFMI values across sports. In addition, sport-specific normative values can be used as benchmarks and targets for training, nutrition, and goal setting.

Military Body Composition Standards and Physical Performance: Historical Perspectives and Future Directions

ABSTRACT

Harty, PS, Friedl, KE, Nindl, BC, Harry, JR, Vellers, HL, and Tinsley, GM. Military body composition standards and physical performance: historical perspectives and future directions. J Strength Cond Res 36(12): 3551-3561, 2022-US military physique and body composition standards have been formally used for more than 100 years. These metrics promote appropriate physical fitness, trim appearance, and long-term health habits in soldiers, although many specific aspects of these standards have evolved as evidence-based changes have emerged. Body composition variables have been shown to be related to many physical performance outcomes including aerobic capacity, muscular endurance, strength and power production, and specialized occupational tasks involving heavy lifting and load carriage. Although all these attributes are relevant, individuals seeking to improve military performance should consider emphasizing strength, hypertrophy, and power production as primary training goals, as these traits appear vital to success in the new Army Combat Fitness Test introduced in 2020. This fundamental change in physical training may require an adjustment in body composition standards and methods of measurement as physique changes in modern male and female soldiers. Current research in the field of digital anthropometry (i.e., 3-D body scanning) has the potential to dramatically improve performance prediction algorithms and potentially could be used to inform training interventions. Similarly, height-adjusted body composition metrics such as fat-free mass index might serve to identify normal weight personnel with inadequate muscle mass, allowing for effective targeted nutritional and training interventions. This review provides an overview of the origin and evolution of current US military body composition standards in relation to military physical readiness, summarizes current evidence relating body composition parameters to aspects of physical performance, and discusses issues relevant to the emerging modern male and female warrior.

Applied sports science and sports medicine in women’s rugby: systematic scoping review and Delphi study to establish future research priorities

Objectives

In part 1, the objective was to undertake a systematic scoping review of applied sports science and sports medicine in women’s rugby, and in part 2 to develop a consensus statement on future research priorities.

Design

In part 1, a systematic search of PubMed (MEDLINE), Scopus and SPORTDiscus (EBSCOhost) was undertaken from the earliest records to January 2021. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020, the PRISMA extension for Scoping Reviews, and the PRISMA extension protocols were followed. In part 2, 31 international experts in women’s rugby (ie, elite players, sports scientists, medical clinicians, sports administrators) participated in a three-round Delphi consensus method. These experts reviewed the findings from part 1 and subsequently provided a list of priority research topics in women’s rugby. Research topics were grouped into expert-based themes and expert-based subthemes via content analysis. Expert-based themes and expert-based subthemes were ranked from very low to very high research priority on a 1–5 Likert scale. Consensus was defined by ≥70% agreement. The median research priority agreement and IQR were calculated for each expert-based theme and subtheme.

Data sources

PubMed (MEDLINE), Scopus and SPORTDiscus (EBSCOhost).

Eligibility criteria for selecting studies

Studies were eligible for inclusion if they investigated applied sports science or sports medicine in women’s rugby.

Results

In part 1, the systematic scoping review identified 123 studies, which were categorised into six sports science and sports medicine evidence-based themes: injury (n=48), physical performance (n=32), match characteristics (n=26), fatigue and recovery (n=6), nutrition (n=6), and psychology (n=5). In part 2, the Delphi method resulted in three expert-based themes achieving consensus on future research priority in women’s rugby: injury (5.0 (1.0)), female health (4.0 (1.0)) and physical performance (4.0 (1.0)).

Summary/Conclusion

This two-part systematic scoping review and Delphi consensus is the first study to summarise the applied sports science and sports medicine evidence base in women’s rugby and establish future research priorities. The summary tables from part 1 provide valuable reference information for researchers and practitioners. The three expert-based themes that achieved consensus in part 2 (injury, female health and physical performance) provide clear direction and guidance on future research priorities in women’s rugby. The findings of this two-part study facilitate efficient and coordinated use of scientific resources towards high-priority research themes relevant to a wide range of stakeholders in women’s rugby.

Sport Differences in Fat-Free Mass Index Among a Diverse Sample of NCAA Division III Collegiate Athletes

ABSTRACT

Brandner, CF, Harty, PS, Luedke, JA, Erickson, JL, and Jagim, AR. Sport differences in fat-free mass index among a diverse sample of NCAA Division III collegiate athletes. J Strength Cond Res XX(X): 000-000, 2022-Fat-free mass index (FFMI) is becoming a popular metric to determine an athlete's potential for future fat-free mass accrual or to identify athletes who may be at risk for low fat-free mass (FFM). The aim of the current study was to examine sport-specific differences in FFMI among a cohort of collegiate athletes. NCAA Division III male (n = 98; age: 20.1 ± 1.6 years, height: 1.82 ± 0.06 m, body mass: 92.7 ± 17.5 kg, %BF: 15.6 ± 8.8%) and female (n = 92; age: 19.45 ± 1.1 years, height: 1.68 ± 0.06 m, body mass: 65.16 ± 11.04 kg, %BF: 22.71 ± 5.9%) athletes completed a body composition assessment using air displacement plethysmography. Fat-free mass index was calculated by dividing FFM by height squared. The mean ± SD FFMI was significantly higher (p < 0.05) for males (23.37 ± 2.41 kg·m-2) compared with females (17.54 ± 1.8 kg·m-2). There was a significant main effect for sport category. Post hoc analysis indicated that throwers had a higher (p < 0.001) FFMI (mean difference, 95% confidence interval) compared with sprinters and soccer athletes (4.17, 2.03-6.32 kg·m-2), endurance and weight-sensitive athletes (4.91, 2.67-7.14 kg·m-2), and court sport athletes (4.39, 1.97-6.81 kg·m-2), respectively, among female athletes. Post hoc analysis indicated that football players had a higher (p < 0.01) FFMI than distance runners (3.89, 2.15, 5.62) and wrestlers (2.23, 0.78, 3.68), among male athletes. These findings indicate that sex differences in FFMI exist, with differences identified between sports. These findings can guide strength and nutritional programming decisions by providing sport-specific normative data profiles.

Resting Metabolic Rate in Female Rugby Players: Differences in Measured Versus Predicted Values

ABSTRACT

O'Neill, JERG, Walsh, CS, McNulty, SJ, Gantly, HC, Corish, ME, Crognale, D, and Horner, K. Resting metabolic rate in female rugby players: differences in measured versus predicted values. J Strength Cond Res 36(3): 845-850, 2022-This study investigated (a) the accuracy of resting metabolic rate (RMR) prediction equations in female rugby players and (b) factors that might explain poor prediction accuracy in some individuals. Resting metabolic rate was assessed in 36 female elite and subelite rugby players (age: 18-35 years, fat-free mass (FFM): 43-63 kg, fat mass %: 15-41%). After pretest standardization (24-hour exercise avoidance and 12-hour overnight fast), RMR was measured by indirect calorimetry and compared with predicted values determined by Harris-Benedict, Cunningham, Ten Haaf, Jagim and Watson equations. Body composition was assessed by air displacement plethysmography, muscle damage indicated by creatine kinase, and risk of low energy availability (LEA) by LEA in Females Questionnaire. Measured RMR was 1,651 ± 167 kcal·d-1. The Cunningham, Ten Haaf, and Watson (body mass) predicted values did not differ from measured (p > 0.05), while all other predicted values differed significantly (p < 0.001). Individually, prediction accuracy to within 10% varied widely depending on the equation used (range 44% [n = 16] to 86% [n = 31]). Three of the 5 individuals whose values were outside 10% of the measured value using the best performing Ten Haaf FFM equation could be explained by muscle damage or LEA. These measures may be useful to assist in understanding why measured RMR may be lower or higher than predicted in some athletes. Overall, the Ten Haaf equations showed the best accuracy, suggesting these equations may be most suitable for this population. The findings demonstrate the importance of considering the population studied when determining the most appropriate prediction equation to use.

Substantiation of Methods for Predicting Success in Artistic Swimming

To develop a methodology for predicting success in artistic swimming based on a set of morphofunctional indicators and indices, 30 schoolgirls, average age (12.00 ± 0.22), were divided into two groups. Group 1: 15 athletes, training experience 4–5 years. Group 2: 15 schoolgirls without training experience. For each participant, we determined the length and weight of the body, the circumference of the chest, vital lung capacity, and the circumference of the biceps in a tense and at rest. The Erisman index, biceps index, and the ratio of proper and actual vital lung capacity was calculated. Them, we conducted the Stange and Genchi hypoxic tests, and flexibility tests for “Split”, “Crab position”, and “Forward bend”. Prediction was conducted using the Wald test with the calculation of predictive coefficients and their informativeness. A predictive table containing results of functional tests and indices of artistic swimming athletes is developed. It includes nine criteria, which informativeness varied in the range of 395.70–31.98. The content of the prediction consists of evaluating the results, determining the appropriate predictive coefficient, and summing these coefficients before reaching one of the predictive thresholds. The conducted research allowed us to substantiate and develop a method for predicting the success of female athletes with the use of morphofunctional indicators and indices.

BODY COMPOSITION AMONG UNIVERSITY FEMALE ATHLETES OF TEAM SPORTS

ABSTRACT Introduction: The assessment of body composition in female athletes of different sports is important for health monitoring. Objective: To compare body composition in university athletes of different team sports (indoor soccer, flag football and volleyball). Methods: A cross-sectional study carried out with 45 female athletes, aged 18 to 35 years (22.8 ± 3.55). The dependent variables were body fat mass (FM) and fat-free mass (FFM) measured by air displacement plethysmography. Bone mineral content, adjusted for height (BMC/height) and bone mineral density (BMD), were measured by dual energy X-ray absorptiometry. The independent variable was sport [flag football (n = 12); indoor soccer (n = 20); volleyball (n = 13)] and the covariates were age (complete years), training volume (minutes per week) and length of time playing the sport (complete years). Analysis of covariance was used. Results: Adjusting the model for covariates, volleyball athletes (19.27 kg ± 2.20) presented higher FM values compared to the flag football (16.00 kg ± 1.70) and indoor soccer players (12.20 kg ± 1.30). There was no significant difference in FFM, BMC/height and total BMD between sports, even after adjusting for covariates. Conclusion: Volleyball athletes presented higher FM compared to flag football and indoor soccer athletes. There were no differences in FFM, BMC/height and BMD among the players of the different team sports. This study can help coaches and other sports professionals to prevent injuries to athletes in sports such as higher FM (volleyball), or to prevent diseases such as menstrual irregularities, which are common in athletes who may have low levels of body fat (indoor soccer players), this being one of the risk factors for the female athlete triad (eating disorders, menstrual irregularities and low BMD). Level of evidence III; Retrospective comparative study .

Assessment of Dietary Intake and Nutritional Status in CrossFit-Trained Individuals: A Descriptive Study

CrossFit is a discipline with high training and nutritional requirements. To date, there is only scarce data evaluating nutrition among CrossFit training and they mostly focus on selected nutritional interventions. Therefore, the purpose of this descriptive study was the assessment of dietary intake and nutritional status in a selected group of CrossFit-trained participants. The study consisted of 62 CrossFit athletes (31 men and 31 women, aged 31.0 ± 5.2 and 30.0 ± 4.3 years, respectively). Body composition was analyzed by electrical bioimpedance. Dietary intake was assessed using a standardized 3-day food record. Body fat percentage for females and males was 20.3 ± 4.3% and 13.7 ± 3.3% respectively. The energy intake in the diet was lower (~1700 kcal in women and ~2300 kcal in men) than the recommended demand. Moreover, low consumption of carbohydrates was stated, as well as an inadequate intake of folate, vitamin E (in women), and minerals, such as Fe and Ca (in women). The energy, carbohydrate, iron, and calcium intake in the CrossFit participants' diet was too low in comparison to recommendations. It seems justified to educate athletes and coaches about nutritional habits, and individual energy and nutrients requirements.

Body Composition and Physical Fitness Profiles of Elite Female Japanese Wrestlers Aged <12 Years until >20 Years

Studies evaluating the physical fitness levels of elite wrestlers during junior high school are limited. This study aimed to examine the body composition and physical fitness profiles of elite Japanese female wrestlers aged <12 years until >20 years. There were 114 elite female wrestlers enrolled. Measurements were conducted in the following age categories: <12 years (U-12), <15 years (U-15), <17 years (U-17: cadet), <20 years (U-20: junior), and >20 years (senior). Body composition variables consisted of body mass index (BMI), percent body fat, fat free mass, and fat free mass index (FFMI). Fitness measurements included grip strength, back strength, sit-up, rope-climbing, and endurance running tests. The wrestlers in this study demonstrated comparable or greater FFMI values (e.g., FFMI: 17.9 ± 0.4 kg/m² for light and 19.8 ± 0.9 kg/m² for heavy weight categories in U-20), when compared with young female wrestlers in previous studies, whereas stature, body mass, and BMI of the wrestlers in our study were unremarkable. Regarding the fitness assessment, a remarkable increase in back strength was observed after late puberty. An outstanding enhancement of muscle strength after late puberty, which is unlikely to occur in ordinary women, would be an important requirement to become the world’s top female wrestler.