Muscle Strength in Athletes improved 1.4 to 19 percent by vitamin D – systematic review June 2016

Effects of Vitamin D Supplementation on Muscle Strength in Athletes A Systematic Review.

J Strength Cond Res. 2016 Jun 28.
Chiang CM1, Ismaeel A, Griffis RB, Weems S.
Nutrition Sciences, Baylor University, Waco, Texas; and 2English, Baylor University, Waco, Texas.

The purpose of this systematic review of the literature was to investigate the effects of vitamin D supplementation on muscle strength in athletes. A computerized literature search of three databases (PubMed, Medline, and Scopus) was performed. Included in the review were randomized controlled trials, published in English, which measured serum vitamin D concentrations and muscle strength in healthy, athletic participants ages 18-45 years old. Quality was assessed using the PEDro scale.
Five randomized controlled trials and one controlled trial were identified, and quality assessment showed five trials were of 'excellent quality' and one was of 'good quality.' Trials lasted from 4 weeks to 6 months and dosages ranged from 600 IU to 5000 IU per day.
Vitamin D2 was found to be ineffective at impacting muscle strength in both studies wherein it was administered
. In contrast, vitamin D3 was shown to have a positive impact on muscle strength. In two studies, strength outcome measures were significantly improved following supplementation (p < 0.05).

In the other two studies administering vitamin D3, there were trends for improved muscle strength. Specifically, improvements in strength ranged from 1.37% to 18.75%. Additional studies are needed to confirm these associations.
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Suspect that most of the benefits were associated with high dose vitamin D

See also Vitamin D Life

• Athletic performance and recovery benefits of Vitamin D (4000-5000 IU and Vitamin K) – Aug 2015
• Vitamin D supplementation improves muscle strength in healthy adults – meta-analysis of 6 RCT Aug 2014
• Muscle strength of senior women increased 25 percent with vitamin D, decreased 6 percent with placebo – Oct 2016

Sports and Vitamin D has the following summary
Athletes are helped by vitamin D by:

1. Faster reaction time
2. Far fewer colds/flus during the winter
3. Less sore/tired after a workout
4. Fewer micro-cracks and broken bones
5. Bones which do break heal much more quickly
6. Increased VO2 and exercise endurance Feb 2011
7. Indoor athletes especially need vitamin D
8. Professional indoor athletes are starting to take vitamin D and/or use UV beds
9. Olympic athletes have used UV/vitamin D since the 1930's
10. The biggest gain from the use of vitamin D is by those who exercise less than 2 hours per day.
11. Reduced muscle fatigue with 10,000 IU vitamin D daily
12. Muscle strength improved when vitamin D added: 3 Meta-analysis
13. Reduced Concussions
    See also: Sports and Vitamin D category 231 items

The Meta-analyses of Sports and Vitamin D