Muscle strength of Judo athletes increased 13 percent following single dose of 150,000 IU vitamin D – RCT

Acute Effects of Vitamin D3 Supplementation on Muscle Strength in Judoka Athletes: A Randomized Placebo-Controlled, Double-Blind Trial.

Clin J Sport Med. 2015 Nov 2

Comment Indoor athletes typcially have low levels of vitamin D (< 30 ng),and so will benefit more than ourdoor athletes from a dose of vitamin D. Data seems reasonable. See also VitaminDWiki * Muscles and Vitamin D - many studies * Many athletes now advised to take daily vitamin D supplements – Aug 2014 * Overview Sports and vitamin D * Vitamin D supplementation improves muscle strength in healthy adults – meta-analysis of 6 RCT Aug 2014 * Elite outdoor athletes had 52 ng of vitamin D – March 2013 * * * items in category Sports** * Sports benefits from up to 50 ng of Vitamin – meta-analysis - Nov 2012 has the following chart Items in both of the categories of Intervention AND Sports {category}

Wyon MA1, Wolman R, Nevill AM, Cloak R, Metsios GS, Gould D, Ingham A, Koutedakis Y.

1*Research Centre for Sport Exercise and Performance, University of Wolverhampton, Walsall, United Kingdom;

†National Institute of Dance Medicine and Science, United Kingdom; ‡Department of Rheumatology and Sport and Exercise Medicine, Royal National Orthopaedic Hospital, Stanmore, United Kingdom;

§Research Centre for Sport Exercise and Performance, University of Wolverhampton, Walsall, United Kingdom;

¶School of Pharmacy, School of Life Sciences, Aston University, Birmingham, United Kingdom; and ‖

Department of Exercise Sciences, University of Thessaly, Trikala, Greece.

OBJECTIVE: Indoor athletes have been shown to be prone to vitamin D3 deficiency. The aim of the study was to examine the acute effects of vitamin D supplementation on muscle function using isokinetic dynamometry.

DESIGN: Randomized placebo-controlled, double-blind study.

SETTING: Institutional.

PARTICIPANTS: Adult male white national level judoka athletes (n = 22) who were involved in full-time training. Exclusion criteria were vitamin supplementation, overseas travel to sunny climes, and/or an injury incurred during the last 3 months before testing.

INTERVENTIONS: Subjects were randomly allocated to the treatment (150 000IU vitamin D3) or placebo and given blinded supplements by an independent researcher. Participants were tested twice, 8 days apart, on a Monday morning before the start of judo training and after 2 days of rest. A 5 to 7 mL of blood sample was collected followed by isokinetic concentric quadriceps and hamstring muscle function assessments on the right leg at 30 and 200°·s.

MAIN OUTCOME MEASURES: Repeated-measures analysis of variance was used to analyze isokinetic muscle force and serum 25(OH)D3. Regression to the mean was used to examine changes in 25(OH)D3 levels over the study period.

RESULTS: The treatment group demonstrated a significant increase in

• serum 25(OH)D levels (34%, P ≤ 0.001) and

• muscle strength (13%, P = 0.01) between days 1 and 8.

No significant differences were found for the placebo group for the same period.

CONCLUSIONS: A single bolus of 150 000 IU vitamin D3 had a significant positive effect on serum 25(OH)D levels and muscle function in vitamin D insufficient elite indoor athletes.

CLINICAL RELEVANCE: Serum 25(OH)D3 levels of indoor athletes should be monitored throughout the year and especially during winter months. Beneficial responses, in muscle strength and serum 25(OH)D3, to 1 dose of vitamin D3 supplementation can be observed within 1 week of ingestion. Muscle strength is linked to serum 25(OH)D levels.

PMID: 26535872

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