title: Longitudinal Body Composition Changes in NCAA Division I College Football Players.
abstract: Trexler, ET, Smith-Ryan, AE, Mann, JB, Ivey, PA, Hirsch, KR, and Mock, MG. Longitudinal body composition changes in NCAA Division I college football players. J Strength Cond Res 31(1): 1-8, 2017-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% (Δ = -1.3 ± 2.5%), LM (Δ = 2.8 ± 2.8 kg), GYN (Δ = -1.5 ± 3.0%), BMC (Δ = 0.06 ± 0.14 kg), and BMD (Δ = 0.015 ± 0.027 g·cm, all p ≤ 0.05). Across 4 years, weight increased significantly (Δ = 6.6 ± 4.1 kg) and favorable changes were observed for LM (Δ = 4.3 ± 3.0 kg), BMC (Δ = 0.18 ± 0.17 kg), and BMD (Δ = 0.033 ± 0.039 g·cm, 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.
authors.affiliation: 1Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, North Carolina; 2Human Movement Science Curriculum, Department of Allied Health Sciences, University of North Carolina, Chapel Hill, North Carolina; Departments of 3Athletics; 4Physical Therapy, University of Missouri, Columbia, Missouri; and 5Office of the Chancellor, University of Missouri, Columbia, Missouri.
authors.forename: Eric T
authors.initials: ET
authors.lastname: Trexler
authors.forename: Abbie E
authors.initials: AE
authors.lastname: Smith-Ryan
authors.forename: J Bryan
authors.initials: JB
authors.lastname: Mann
authors.forename: Pat A
authors.initials: PA
authors.lastname: Ivey
authors.forename: Katie R
authors.initials: KR
authors.lastname: Hirsch
authors.forename: Meredith G
authors.initials: MG
authors.lastname: Mock
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D056352:Athletes; D001823:Body Composition / Q000502:physiology*; D001837:Body Weights and Measures; D015519:Bone Density; D005538:Football / Q000502:physiology*; D006801:Humans; D008297:Male; D012621:Seasons; D014495:Universities; D055815:Young Adult