Body Composition Flashcards

A CSSD uses DXA to assess a 55-year-old masters female triathlete. Which body composition change is most expected compared to her values at age 30?

Answer: Decreased lean mass and increased fat mass even with maintained exercise habits

Sarcopenia (age-related muscle loss) and hormonal changes with menopause lead to decreased fat-free mass and increased fat mass, even in athletes who maintain training, making body composition monitoring important in masters athletes.

A sports dietitian notices that a male cyclist's skinfold sum has increased 10 mm over 6 weeks despite maintained training. The most appropriate next step is:

Answer: Assess energy intake, training load changes, and stress or recovery status before making dietary changes

A meaningful increase in skinfold sum warrants a full assessment of diet, training, sleep, and stress before intervening, as multiple factors can drive fat gain and nutrition changes should be evidence-based.

Which of the following best explains why athletes from African American backgrounds may have DXA body fat estimates that are lower than their actual fat mass?

Answer: DXA software is calibrated using European reference populations with lower bone mineral density

DXA reference equations were largely derived from European populations; African American individuals tend to have higher bone mineral density, causing DXA to over-attribute tissue to lean mass and underestimate fat mass.

In the context of sport, what does 'percent body fat at which performance is optimized' most accurately reflect?

Answer: The individualized fat level at which power-to-weight ratio and health markers are both favorable

Optimal performance body fat is highly individual and sport-specific; it represents the balance point where power-to-weight or strength-to-weight ratio is maximized without compromising health or hormonal function.

Which equation is most appropriate for estimating percent body fat from body density in lean, highly trained male athletes?

Answer: A population-specific equation validated in athletes, such as the Withers or Modlesky equation

Athlete-specific conversion equations account for the higher bone mineral density and lower total body water percentage in elite athletes, producing more accurate body fat estimates than general population equations.

A collegiate wrestling program implements the NCAA Minimum Weight Certification Program. What is the primary body composition criterion used to establish an athlete's minimum competition weight?

Answer: Minimum weight is set at the athlete's weight when body fat reaches 7% (males) or 12% (females)

The NCAA minimum weight certification uses 7% body fat for males and 12% for females as the floor; the weight at which the athlete would reach that threshold is their certified minimum competition weight.

A CSSD is counseling a Paralympic powerlifter with a lower-limb amputation about body composition assessment. Which consideration is most important?

Answer: Standard two-compartment equations are invalid because amputation alters the assumed relationship between body density and fat mass

Amputation changes the proportions of bone, muscle, and fat relative to total body weight, violating the assumptions embedded in standard 2-compartment body density equations; athlete-specific or multicompartment approaches are recommended.