The active form o Vitamin D is a steroid in the same way that testosterone is asteroid and vitamin D is a hormone in the same way that growth hormone is a hormone. Steroid hormones are substances made from cholesterol, which circulate in the body and work at distinct sites but setting in motion genetic protein transcription. That is both Vitamin D and testosterone set in motion your genome, the stuff of lie. While testosterone is a sex hormone, Vitamin D is a pleomorphic (multiple function) steroid hormone.
If you are vitamin D deficient, the medical literature indicates that the right amount of Vitamin D will make you faster, stronger, improve your balance and timing, etc. How much of it will improve your athletic ability depends on how deficient you are to begin with.
Peak athletic performance also depends upon the neuromuscular cells in your body and brain having unfiltered access to the steroid hormone, activated Vitamin D. How much activated vitamin D is available to brain, muscle, and nerves depends on how much 25-hydroxy-vitamin D in your blood. In turn, how much 25-hydroxy-vitamin d is in your blood depends on how much vitamin D you put in your mouth or how often you expose your skin to uvb light.
