PS plays an important role in cell membranes and thus can be found all over the body including muscle cells. Some research has shown PS supplementation can reduce the stress response to exercise and there is reason to believe it may work to enhance muscle energetics and therefore exercise performance. Recent work from researchers in the United Kingdom provides preliminary evidence that PS may provide a performance benefit to athletes. Healthy men were provided either PS (750 mg/day) or placebo for a total of 10 days. An intense exercise test was performed at 85% of maximal oxygen capacity before and after this 10 day supplementation period. The main finding was that the PS group could exercise for 2 minutes longer after supplementation (7:51 to 9:51 min) whereas the placebo group had no change in performance. The exact mechanism explaining this ergogenic effect of PS was not examined but the authors suggest that supplementation could enhance membrane PS content and affect muscle contraction in some manner.

Kingsley MI, Miller M, Kilduff LP, McEneny J, Benton D. Effects of phosphatidylserine on exercise capacity during cycling in active males. Med Sci Sports Exerc. 2006 Jan;38(1):64-71