Rogers, S., Perez, G. M., & Hew-Butler, T. D. (2023). Fit Or Fat? Sex Differences In BMI And Body Composition In Collegiate Athletes And Non-athletes:

Fat-Free Mass Index (FFMI) in Elite Athletes

• FFMI is a measure that indicates body composition focusing on lean mass relative to height.
• Elite athletes showed a 9.2% greater FFMI compared to a cohort of recreational CrossFit athletes.
  • Elite Athletes: 20.8 kg/m²
  • Cohort: 19.0 ± 2.2 kg/m²
• Body composition analysis revealed:
  • Elite athlete’s sum of skinfold measures: 51.7 mm
  • Cohort’s skinfold measures: 107.4 ± 45.5 mm
  • Represents a 51.9% decrease in fat measures for elite athletes.
• Metabolic analysis conducted showed:
  • Resting Metabolic Rate (RMR): 13.8% higher in elite athlete
  • Relative Resting Energy Expenditure: 19.4% higher in elite athlete.
• Conclusion:
  • Elite female CrossFit competitor has significantly higher lean mass and lower fat mass compared to recreational athletes.
  • Indicates need for more research to explore the implications of body composition on CrossFit performance.

Study on BMI and Body Composition in Collegiate Athletes & Non-Athletes

• Purpose: Evaluate BMI, body composition, handgrip strength, and depression levels.
• Methods:
  • 258 participants included NCAA D2 athletes, collegiate non-athletes, and older non-athletes.
  • Measures taken: height, weight (stadiometer), whole body composition (DXA scan), handgrip strength (dynamometer), depression (CES-D scale).
  • Statistical tests: 1-way ANOVA, Pearson’s correlation.
• Results:
  • Mean age of participants: 22 ± 7 years; overall BMI: 27 ± 5 kg/m².
  • Football players classified as overweight (BMI = 29 ± 5 kg/m²) but showed:
  • Highest lean mass: (F = 11.9; p < 0.001)
  • Handgrip strength: (F = 5.4; p < 0.001)
  • Differences in lean mass and strength noted between male and female athletes.
  • Correlations among BMI and body composition revealed significant relationships, but no correlation with depression.
• Conclusions:
  • Strength-trained athletes misclassified as overweight due to high lean mass, emphasizing their fitness level.
  • Suggests a U-shaped relationship for body composition gains.

Validity of Bioelectrical Impedance Analysis (BIA) for Body Composition in Gymnasts

• Purpose: Assess validity of BIA methods for estimating body fat percentage in collegiate female gymnasts.
• Methods:
  • Compared two BIA analyzers (InBody 230 and Omron HBF-306) against DXA reference values.
  • Participants: 67 female gymnasts, with measurements on hydration levels monitored.
• Results:
  • Mean % fat from estimates:
  • InBody: 22.20 (±4.51)
  • Omron: 20.92 (±2.83)
  • DXA: 25.25 (±4.18)
  • ANOVA indicated significant differences in % fat among BIA analyzers and DXA.
  • BIA analyzers underestimated % fat compared to DXA.
• Conclusions:
  • Neither BIA method provides a valid measure of body fat in female collegiate gymnasts, recommending against their use in this population.

Impact of Wilderness Backpacking on Body Composition and Metabolism

• Study Overview: Examined how a multi-month backpacking experience affects body composition and resting metabolism.
• Importance of Body Composition Analysis:
  • Understanding body composition changes in physically demanding environments provides insights into health and performance.
    \n- Key Focus Areas for Future Research:
  • Effects of prolonged physical activity on metabolic rate and health outcomes for athletes.
  • Importance of body composition profiles as indicators for athletic performance and wellbeing.