From this NYT article, Men, Women and Speed. 2 Words: Got Testosterone?:
“The hormone (testosterone) affects everything from muscle size and strength to the size of the heart to the amount of oxygen-carrying blood cells in the body to the percentage of fat on an athlete’s body”. 
And this:
“Testosterone, Levine said, gives men what he calls a bigger and better-fueled engine. Their skeletal muscles, which do the work during exercise, are bigger. And their hearts, which provide fuel for the work, are bigger, too.”
The article goes on to say that more testosterone results in more type-2 muscles which are used for power and speed, and that more testosterone results in muscle being better able to store energy, glycogen. Testosterone makes for bigger muscles, stronger hearts, less fat, more hemoglobin, more type-2 fiber, and more glycogen - that is quiet an advantage to those who have more of it. The article states that men have more testosterone than women and hence the resulting differences in speed. What to do outside of taking drugs? Strength training has been shown to in increase testosterone levels in men and women.
Significant strength increases occur exercising as little as once or twice a week IF it's the right exercise program with the right trainer. At Kelly's Austin Personal Training and at New Orleans Ultimate Fitness Trainers our personal trainers can guide you through a personal training program that will safely produce ongoing results.
