Relationship of Fat-Free Mass and Fat Mass to Body Weight in College Male Athletes Players

Body mass differs widely across the sports spectrum. While some sports are dominated by large athletes, other sports participants benefit from a small size or weight class restrictions. Perhaps the most frequent measurement of body composition has been %fat with less frequent emphasis on the major components of body composition, fat-free mass (FFM) and fat mass (FM). FFM is the functional component as it is closely associated with maximal voluntary strength, while FM plays an important role in energy balance. With the ever increasing emphasis on control and manipulation of these components in modern sports, perhaps there should be greater focus on the relationship between FFM and FM. PURPOSE: To determine the relationship of FFM and FM to height and body mass across the wide range of size typically observed in college athletes. METHODS:Two hundred and sixty-seven NCAA D-II male athletes (age = 20.2 ± 1.2 y, height =180.6 ± 7.9 cm, body mass = 87.3 ± 16.9 kg) volunteered to serve as subjects. Body composition was assessed using dual-energy x-ray absorptiometry (DEXA). This allowed compartmentalization and regional estimates of lean (bone, muscle, etc.) and fat tissue from which FFM and FM are determined. RESULTS: The relationship between height and body mass are curvilinear and moderately correlated (r=0.61). FFM and FM were significantly related to height (r = 0.69 and 0.35, respectively) and body mass (r = 0.92 and 0.91, respectfully), with the relationships being more curvilinear in the latter. FM accounted for 60% of the variance in body mass, while FFM accounted for only 40%. The relationship between FFM and FM was significant (r = 0.62) and curvilinear, showing a greater accumulation of FM at higher body masses. CONCLUSIONS: FFM and FM increase linearly with height, but showed a curvilinear relationship with body mass suggesting that this population of male athletes may be approaching a theoretical limit of FFM accumulation. In contrast, the accumulation of FM follows a linear pattern with height but increases exponentially with body mass. The curvilinear relationship between body weight and height is not typical and appears to be related to a relative increase in body weight with fat accumulation beyond 180 cm height and 110 kg body weight. Depending on the sport, accumulation of FM may become a hindrance to performance.