Bisch, Katie2018-09-212018-09-212018-06https://hdl.handle.net/11299/200152University of Minnesota M.S. thesis. June 2018. Major: Kinesiology. Advisor: Donald Dengel. 1 computer file (PDF);viii, 59 pages.PURPOSE: The primary objective was to identify normative values for total and regional body composition by position among female NCAA Division I collegiate volleyball players using dual X-ray absorptiometry (DXA). The secondary objective was to analyze pre- to post-season body composition changes. METHODS: Ninety female volleyball players (age=19.8±1.4 years, height=179.7±8.5 cm, body mass=74.7±9.9 kg) from multiple NCAA Division I universities received a DXA scan. Athletes were categorized by position: Middle Blocker (MB=31), Outside Hitter (OH=32), Setter (ST=9), and Libero (LB=18). Total and regional fat mass (FM), lean masses (LM), and bone mineral density (BMD) were measured by DXA, as well as abdominal visceral adipose tissue (VAT). Upper total mass to lower total mass ratio (ULR), total upper mass to lean lower mass ratio (TULLR), lean upper mass to lean leg mass ratio (LULLR), and gynoid lean mass to leg lean mass ratio (GLR) were also calculated. Pre- to post-season changes in body composition were assessed among 39 volleyball players in the cohort from three universities (age=19.3±1.0 years, height=179.7±9.0 cm, body mass=73.4±8.7 kg). An analysis of variance with TukeyHSD post-hoc comparisons assessed differences in body composition measures between positions, while paired t-tests assessed pre- to post-season differences. Effect size was calculated for each variable and magnitude based inferences were computed to draw inferences from the data. RESULTS: As expected, height was statistically significant between all positions: MB (185.9±4.6 cm, p<0.001), OH (181.7±4.1 cm, p<0.001), and ST (174.7±3.7 cm, p=0.009) were all significantly taller than LB (167.8±8.0 cm). Weight was significantly greater in MB and OH (80.0±9.2 kg, 76.7±7.8 kg) compared to LB (64.5±7.6 kg, p<0.001), and in MB compared to ST (69.7±5.7 kg, p=0.006). Percent body fat (p=0.74), body mass index (BMI) (p=0.94), and VAT (p=0.143) were not significant between positions. Total LM was greater in MB and OH (55.7±4.6, 54.1±4.7 kg) compared to LB (45.9±4.9 kg, p<0.001) and ST (48.3±3.2 kg, p=0.002, p=0.006, respectively). Total FM was significantly greater in MB compared to LB (21.0±6.9, 16.1±4.0 kg, p=0.016). Trunk LM was greater in MB and OH (26.0 ± 2.0 kg, 25.3 ± 2.3 kg) compared to LB (22.1 ± 2.3 kg, p<0.001, both) and ST (23.1 ± 1.4 kg, p=0.003, p=0.03, respectively). Leg LM was greater in MB and OH (20.4 ± 2.1 kg, 19.4 ± 2.1 kg) compared to LB (15.7 ± 2.0 kg, p<0.001, both) and ST (17.0 ± 1.3 kg, p<0.001, p=0.009, respectively). Arm LM was greater in MB and OH (6.2 ± 0.7 kg, 6.1 ± 0.7 kg) compared to LB (5.1 ± 0.7 kg, p<0.001, both) and ST (5.2 ± 0.6 kg, p=0.003, p=0.004, respectively). Leg FM was significantly greater in MB compared to LB (8.7 ± 2.6 kg, 6.5 ± 1.6 kg, p=0.002). However, trunk FM, arm FM, and VAT mass were not significantly (p>0.05) different between positions. ULR was lower in MB (1.48±0.11, p<0.001) and OH (1.51±0.11, p=0.012) compared to LB (1.61±0.1), and lower in MB versus ST (1.59±0.07, p=0.043). In relation to LB (0.48±0.03), GLR was lower in MB (0.44±0.02, p<0.001) and OH (0.46±.04, p=0.021), and lower in MB compared to ST (0.48±0.02, p=0.021). LULLR was also significantly lower in MB (1.58±0.1, p<0.001) and OH (1.63±0.12, p=0.012) compared to LB (1.73±0.09), but not ST (1.67±0.06). TULLR was not significantly different (p=0.054). After adjusting for mass, total BMD was significantly greater in MB (1.39±0.1 g/cm2, p<0.001) and OH (1.41±0.09 g/cm2, p=0.002) compared to LB (1.30±0.08 g/cm2), but not ST (1.31±0.07 g/cm2, p>0.05). Leg BMD was greater in MB and OH (1.54±0.11, 1.53±0.11 g/cm2) compared to LB (1.38±0.09 g/cm2, p<0.001, both) and ST (1.4±0.06 g/cm2, p=0.004, p=0.008, respectively). Spine BMD was greater in MB and OH (1.32±0.15, 1.33±0.12 g/cm2) compared to LB (1.22±0.09 g/cm2, p=0.03), but not ST (1.25±0.1 g/cm2, p>0.05). Arm BMD was not statistically significant between positions (p=0.11). Leg FM significantly decreased from the pre- (7.4±1.7 kg) to post-season (7.0±1.4 kg, p=0.001), a moderate effect size was observed (r=-0.36). No further significant seasonal changes were identified at an adjusted p-value (p<0.007). CONCLUSION: Total body composition measures vary significantly by position; however, differences in total lean mass (p<0.001) are significantly influenced by height. Positional analysis revealed that front row players (MB and OH) have a greater amount of lean mass in their legs compared to non-front row players (ST and LB). Lean mass distribution among front row players is more evenly dispersed between the upper and lower body. BMD differences may be influenced by repeated impacts of jumping during the attacking and blocking actions of front row players. The moderate effect size observed in leg FM suggests that ~95% of players experienced a trivial reduction in leg FM from pre- to post-season. Future studies should longitudinally evaluate the relationship between regional body composition and sport performance.enBody CompositionBone-mineral DensityDual- X-ray AbsorptiometryVolleyballThesis or Dissertation