Vitamin D and exercise performance in professional soccer players.

Nikolaos E Koundourakis,Nikolaos E Androulakis,Niki Malliaraki,Andrew N Margioris,Markus M Heimesaat

doi:10.1371/journal.pone.0101659

Nikolaos E Koundourakis, Nikolaos E Androulakis + Show 3 more

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https://doi.org/10.1371/journal.pone.0101659

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Journal: PloS one	Publication Date: Jul 3, 2014
Citations: 119	License type: CC BY 4.0

Affiliation: University of Crete, University Hospital of Heraklion

Abstract

AimThe current study had two aims. The primary purpose was to examine the association between serum vitamin D levels and the ergometric evaluation of muscle strength, aerobic capacity, and speed in professional soccer players. The secondary aim was to evaluate the effects of the soccer off-season period on serum vitamin D levels.MethodsSixty-seven Caucasian male soccer players (age 25.6±6.2 and height 1.81±0.08 m), members of two Greek Superleague Soccer teams and one Football-league championship team participated in this study. Exercise performance testing for the determination of squat jump (SJ), countermovement jump (CMJ), 10 (10 m) and 20 meters (20 m) sprint performance, maximal oxygen consumption (VO2max), anthropometry, and blood sampling were performed before (pre) and after (post) the six-week off-season period.ResultsAnalysis of our results showed the following: (a) a significant correlations between serum vitamin D levels and performance parameters in both pre (SJ; P<0.001, CMJ; P<0.001, VO2max; P<0.001, 10 m; P<0.001, and 20 m; P<0.001) and post (SJ; P<0.001, CMJ; P<0.001, VO2max; P = 0.006, 10 m; P<0.001, and 20 m; P<0.001) experimental sessions. (b) Vitamin D concentration increased significantly (P<0.001) following the six-week off-season period compared to baseline, while at the same time all measured performance parameters decreased (SJ; P<0.001, CMJ; P<0.001, 10 m; P<0.001, 20 m; P<0.001, VO2max; P<0.001).DiscussionOur findings suggest that vitamin D levels are associated with the ergometric evaluation of muscle strength, as expressed by SJ and CMJ, sprinting capacity, and VO2max in professional soccer players, irrespective the levels of performance. Furthermore, our data reaffirm the importance of UVB on serum vitamin D levels. Moreover, reductions in exercise training stress may also have beneficial effects on vitamin D levels, suggesting a possible association of its levels and the training-induced stress. Our results indicate a possibly bidirectional interaction between soccer performance indices and vitamin D levels.

Highlights

Vitamin D is primarily synthesized endogenously following cutaneous exposure to ultraviolet B radiation (UVB) [1], [2]
Analysis of our results revealed a significant positive correlation between vitamin D levels and squat jump (SJ), CM, and VO2max values at the beginning and at the end of the experimental period
Analysis of our data revealed significant reductions in SJ, countermovement jump (CMJ), VO2max, 10m, and 20m values at the end of the study compared to baseline

Summary

Introduction

Vitamin D is primarily synthesized endogenously following cutaneous exposure to ultraviolet B radiation (UVB) [1], [2]. It has been shown that vitamin D levels correlate with grip and quadriceps strength, physical fitness, and a decline of falls and bone fractures [5], [6]. A recent study on adolescent girls reported a positive association between serum vitamin D levels and jump height, jump velocity, and power [2]. Early studies on collegiate athletes and students have documented that cardiovascular fitness, muscle endurance, and speed are enhanced following exposure to ultraviolet radiation [8], other authors failed to document such associations [9]. A consisted literature indicates that physical and athletic performance is seasonal, it peaks when vitamin D levels peaks and declines as its levels decline [10], [11]

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