I don't know jack **** about endurance sports and winstrol, but it was a favorite of many of my friends who were cornerbacks. It supposedly shaved a little time off their 40. If i were to take a good injectable wintrol (zambon) if they are even still made i would start at around 50mg every 3 days. that i think would do the job without causing too many sides. Possibly every 4 days if he wanted to start and see. If he only had the pills, i would start around 20mg a day.