The Effects of Vitamin D3 on Musculoskeletal Performance in College Aged Males

Abstract

Vitamin D (Vit D) plays an important role in the musculoskeletal system and additionally can be deficient in some segments of the population. PURPOSE: The present study examined the effects 4 weeks of Vit D supplementation versus placebo on musculoskeletal and psychomotor performance. METHODS: The participants were 32 college age males (Age: 22±4 y, Height: 177.7±8.3 cm, Weight: 81.5±14.6 kg, BF%: 19.6±7.9, Vit D: 20.0±7.2ng/ml). Participants were randomly assigned to group (Vit D vs placebo) and remained blind to the treatment throughout the study. The treatments consisted of 4000 IU of Vitamin D3 or similarly sized placebo (dextrose) administered daily for 4 weeks. The participants underwent baseline testing for isometric strength, explosive ability and psychomotor performance, which was repeated at week 2 and week 4. Isometric tests consisted of an isometric mid thigh pull (IMTP) on a force plate and an upper body isometric test (UBIST) using a load cell. Peak force during a countermovement jump (CMJ) was also determined via force plate. A psychomotor vigilance test (PVT) was used to measure sustained reaction time. RESULTS: For UBIST there was a significant effect of group (F=4.52, p=0.04) but not a significant group*time interaction (F=0.18, p=0.84; Vit D pre: 553.7± 168.3N, post: 585.5± 150.2N; Placebo pre: 677.7±182.3N, post: 649.8± 236.9N). For IMTP no significant effect of group (F=0.92, p=0.34) nor significant group*time interaction (F=0.17, p=0.83; Vit D pre: 2596.4±342.3N, post: 2606.9±378.3N; Placebo pre: 2684.0±432.9N, post: 2762.6±440.4N) was found. CMJ analysis did not reveal a significant main effect for group (F=0.75, p=0.39) or interaction effects for group*time (F=1.63, p=0.21; Vit D pre: 4429.7±1619.0N, post: 4938.5±2374.8N; Placebo pre: 5537.3±3027.0N, post: 6266.9±4577.3N). For PVT (mean reaction time) there was no significant main effect for treatment (F= 1.29, p=0.29) or interaction effects for group*time (F= 1.08, p=0.35; Vit D pre: 0.304±0.041sec, post: 0.301±0.053sec; Placebo pre: 0.295±0.044sec, post: 0.284±0.029sec). CONCLUSION: Four weeks of Vitamin D supplementation was not effective in increasing musculoskeletal or psychomotor performance in college aged males. Further research is needed to clarify the effect of vitamin D on recreationally active persons.