Effects Of Seasonal Vitamin D3 Supplementation On Strength, Power, And Body Composition In College Swimmers
Notes for this study:
|Number of Subjects
In a randomized, double-blind, placebo-controlled trial, 19 swimmers took 5,000 IU of vitamin D or placebo daily for 12 weeks during winter.
There was a greater improvement for squat, deadlift, and vertical jump in the vitamin D group, while the difference for bench press, standing broad jump, dips, and pull-ups wasn't statistically significant.
There was a smaller reduction in testosterone and free testosterone for male participants who took vitamin D, whereas there was a comparable reduction in testosterone for female participants, though free testosterone was higher for the vitamin D group. Sex hormone-binding globulin (both male and female combined) increased more in the placebo group, while there was a greater increase in IGF-1, though this wasn't statistically significant.
Vitamin D level was 121.8 nmol/L at baseline.