Increasing evidence indicates that compromised vitamin D status, as indicated by serum 25-hydroxyvitamin D (25-OH D), is associated with decreased muscle function. The purpose of this study was to determine the vitamin D status of collegiate athletes residing in the southern U.S. and its effects on muscular strength and anaerobic power. Collegiate athletes (n = 103) from three separate NCAA athletic programs were recruited for the study. Anthropometrics, vitamin D and calcium intake, and sun exposure data were collected along with serum 25-OH D and physical performance measures (Vertical Jump Test, Shuttle Run Test, Triple Hop for Distance Test and the 1 Repetition Maximum Squat Test) to determine the influence of vitamin D status on muscular strength and anaerobic power. Approximately 68% of the study participants were vitamin D adequate (>75 nmol/L), whereas 23% were insufficient (75–50 nmol/L) and 9%, predominantly non-Caucasian athletes, were deficient (<50 nmol/L). Athletes who had lower vitamin D status had reduced performance scores (p < .01) with odds ratios of 0.85 on the Vertical Jump Test, 0.82 on the Shuttle Run Test, 0.28 on the Triple Hop for Distance Test, and 0.23 on the 1 RM Squat Test. These findings demonstrate that even NCAA athletes living in the southern US are at risk for vitamin D insufficiency and deficiency and that maintaining adequate vitamin D status may be important for these athletes to optimize their muscular strength and power.
R.A. Hildebrand is with the College of Health Sciences, The University of Tulsa, Tulsa, OK. Miller and Warren are with the 2School of Applied Health and Educational Psychology, Oklahoma State University, Stillwater, OK. D. Hildebrand and Smith are with the Dept. of Nutritional Sciences, Oklahoma State University, Stillwater, OK.