Bone Mineral Content and Density Among Female NCAA Division I Athletes Across the Competitive Season and Over a Multi-Year Time Frame.

Stanforth, D, Lu, T, Stults-Kolehmainen, MA, Crim, BN, and Stanforth, PR. Bone mineral content and density among female NCAA Division I athletes across the competitive season and over a multi-year time frame. J Strength Cond Res 30(10): 2828-2838, 2016-Longitudinal and cross-sectional bone mineral content (BMC) and bone mineral density (BMD) comparisons were made among impact and nonimpact sports. Female collegiate athletes, 18-23 years of age, from basketball (BB; n = 38), soccer (SOC; n = 47), swimming (SW; n = 52), track sprinters and jumpers (TR; n = 49), and volleyball (VB; n = 26) had BMC/BMD measures preseason and postseason over 3 years. Control groups of 85 college females, 18-24 years of age, who completed 2 tests 1-3 years apart and of 170 college females, 18-20 years of age, were used for the longitudinal and cross-sectional analyses, respectively. A restricted maximum likelihood linear mixed model regression analysis with a compound symmetric heterogeneous variance-covariance matrix structure was used for all analyses (p ≤ 0.05). Increases from year-1 preseason to year-3 postseason included the following: total BMC (3.3%), total BMD (1.4%), and spine BMD (4.5%) for BB; total BMC (1.5%) and leg BMD (1.2%) for SOC; arm (1.8%), leg (1.9%), and total BMD (5.7%) for SW; total BMC (2.0%), arm (1.7%), leg (2.3%), pelvis (3.4%), spine (6.0%), and total BMD (2.3%) for TR; and arm (4.1%), leg (2.0%), pelvis (2.0%), spine (2.0%), and total BMD (2.7%) for VB. Comparisons among sports determined that BB had higher BMC and BMD values than all other sports for all variables except spine and total BMD; BB, SOC, TR, and VB had higher total BMC (11-29%), leg BMD (13-20%), and total BMD (9-15%) than SW and CON, and there were few differences among SOC, TR, and VB. In conclusion, small, significant increases in many BMC and BMD measures occur during female athlete's collegiate careers. The BMC and BMD differences between impact and nonimpact sports are large compared with smaller differences within impact sports.

Body composition changes among female NCAA division 1 athletes across the competitive season and over a multiyear time frame.

Body composition can affect athletic performance. Numerous studies have documented changes in body composition in female collegiate athletes from pre- to postseason; however, longitudinal studies examining changes across years are scarce. Therefore, the primary purpose of this study was to assess longitudinal body composition changes among female collegiate athletes across 3 years. Two hundred twelve female athletes from basketball (BB; n = 38), soccer (SOC; n = 47), swimming (SW; n = 52), track (sprinters and jumpers; TR; n = 49), and volleyball (VB; n = 26) with an initial mean age of 19.2 ± 1.2 years, height of 172.4 ± 8.9 cm, and total mass of 66.9 ± 9.0 kg had body composition assessments using dual-energy x-ray absorptiometry pre- and postseason over 3 years. A restricted maximum-likelihood linear mixed model regression analysis examined body composition differences by sport and year. Changes (p < 0.05) over 3 years included the following: Lean mass increased in VB from year 1 to 2 (0.7 kg), year 2 to 3 (1.1 kg), and year 1 to 3 (1.8 kg) and in SW from year 1 to 3 (0.6 kg); and percent body fat (%BF) increased in BB from year 1 to 3 (1.7%). There were no changes in SOC or TR. These results indicate that during their college careers, female collegiate athletes can be expected to maintain their %BF and athletes in sports like SW and VB can anticipate an increase in lean mass, but the increases may be less than many athletes, coaches, and trainers envision.