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Open Access Highly Accessed Research

Supplemental vitamin D enhances the recovery in peak isometric force shortly after intense exercise

Tyler Barker1*, Erik D Schneider2, Brian M Dixon2, Vanessa T Henriksen1 and Lindell K Weaver34

Author Affiliations

1 The Orthopedic Specialty Hospital, 5848 S. Fashion Blvd., Murray, UT 84107, USA

2 USANA Health Sciences, Inc, Salt Lake City, UT 84120, USA

3 Hyperbaric Medicine, Intermountain Medical Center, Murray, UT, USA 84107 and LDS Hospital, Salt Lake City, UT 84143, USA

4 University of Utah, School of Medicine, Salt Lake City, UT 84132, USA

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Nutrition & Metabolism 2013, 10:69  doi:10.1186/1743-7075-10-69

Published: 6 December 2013

Abstract

Background

Serum 25-hydroxyvitamin D (25(OH)D) concentrations associate with skeletal muscle weakness (i.e., deficit in skeletal muscle strength) after muscular injury or damage. Although supplemental vitamin D increases serum 25(OH)D concentrations, it is unknown if supplemental vitamin D enhances strength recovery after a damaging event.

Methods

Reportedly healthy and modestly active (30 minute of continuous physical activity at least 3 time/week) adult males were randomly assigned to a placebo (n = 13, age, 31(5) y; BMI, 26.9(4.2) kg/m2; serum 25(OH)D, 31.0(8.2) ng/mL) or vitamin D (cholecalciferol, 4000 IU; n = 15; age, 30(6) y; BMI, 27.6(6.0) kg/m2; serum 25(OH)D, 30.5(9.4) ng/mL) supplement. Supplements were taken daily for 35-d. After 28-d of supplementation, one randomly selected leg performed an exercise protocol (10 sets of 10 repetitive eccentric-concentric jumps on a custom horizontal plyo-press at 75% of body mass with a 20 second rest between sets) intended to induce muscle damage. During the exercise protocol, subjects were allowed to perform presses if they were unable to complete two successive jumps. Circulating chemistries (25(OH)D and alanine (ALT) and aspartate (AST) aminotransferases), single-leg peak isometric force, and muscle soreness were measured before supplementation. Circulating chemistries, single-leg peak isometric force, and muscle soreness were also measured before (immediately) and after (immediately, 1-h [blood draw only], 24-h, 48-h, 72-h, and 168-h) the damaging event.

Results

Supplemental vitamin D increased serum 25(OH)D concentrations (P < 0.05; ≈70%) and enhanced the recovery in peak isometric force after the damaging event (P < 0.05; ≈8% at 24-h). Supplemental vitamin D attenuated (P < 0.05) the immediate and delayed (48-h, 72-h, or 168-h) increase in circulating biomarkers representative of muscle damage (ALT or AST) without ameliorating muscle soreness (P > 0.05).

Conclusions

We conclude that supplemental vitamin D may serve as an attractive complementary approach to enhance the recovery of skeletal muscle strength following intense exercise in reportedly active adults with a sufficient vitamin D status prior to supplementation.

Keywords:
Vitamin D; Muscle strength; Muscle damage; Exercise