Abstract
Many athletes seek to optimize body composition to fit the physical demands of their sport. American football requires a unique combination of size, speed, and power. The purpose of the current study was to evaluate longitudinal changes in body composition in Division I collegiate football players. For 57 players (mean +/- SD, age = 19.5 +/- 0.9 years, height = 186.9 +/- 5.7 cm, weight = 107.7 +/- 19.1 kg), body composition was assessed via dual-energy x-ray absorptiometry in the off-season (March-Pre), end of off-season (May), mid-July (Pre-Season), and the following March (March-Post). Outcome variables included weight, body fat percentage (BF%), fat mass, lean mass (LM), android and gynoid (GYN) fat, bone mineral content (BMC), and bone mineral density (BMD). For a subset of athletes (n = 13 out of 57), changes over a 4-year playing career were evaluated with measurements taken every March. Throughout a single year, favorable changes were observed for BF% (Delta = -1.3 +/- 2.5%), LM (Delta = 2.8 +/- 2.8 kg), GYN (Delta = -1.5 +/- 3.0%), BMC (Delta = 0.06 +/- 0.14 kg), and BMD (Delta = 0.015 +/- 0.027 g.cm(-2), all p <= 0.05). Across 4 years, weight increased significantly (Delta = 6.6 +/- 4.1 kg) and favorable changes were observed for LM (Delta = 4.3 +/- 3.0 kg), BMC (Delta = 0.18 +/- 0.17 kg), and BMD (Delta = 0.033 +/- 0.039 g.cm(-2), all p >= 0.05). Similar patterns in body composition changes were observed for linemen and non-linemen. Results indicate that well-trained collegiate football players at high levels of competition can achieve favorable changes in body composition, even late in the career, which may confer benefits for performance and injury prevention.
