Mauresmo also looks "questionable." Years ago I saw footage on French TV of one of her practice sessions when she was in her late teens and she was really stick thin. She has put on WAY too much muscle mass since then for it to seem un-enhanced.

R

A few reasons why I don’t believe the pros use steroids:

1) Steroids increase the strength of muscle tissue, and not of the tendons that attach the muscles to bone. This is why athletes who use steroids are very susceptible to tendon tears (see Barry Bonds for a prime example). Over the course of a grueling 10-month season, in a sport that places such high strain on tendon tissues, you would expect to see a huge amount of tendon tears in the upper bodies of tour players who use steroids. This simply isn’t the case.

2) Muscle mass doesn’t have a direct correlation with power on the tennis court. Witness players like Roddick, Federer, or Murray, all of whom can get kinda scrawny late in the season, but still hit with incredible power.

3) “Proper” use of steroids occurs in cycles, one month on, one month off. Most pro athletes who have been accused of steroid abuse put on their bulk over the course of a 4 or 5 month off-season (cycling, baseball, football). There isn’t time enough to do that in the 10 weeks of the tennis off-season.

4) Lastly, there are several red-flag signs of steroid abuse that are pretty hard to hide. First of all, steroid users have bad acne on all areas of their body. In a sport where athletes wear pretty skimpy clothing and have fairly intimate dressing quarters, this would be pretty hard to hide. Second, steroid users often will have swollen heads (physically) and show signs of skin stretching in the jowls, due to the fact that the testosterone is bulking up all the muscles in the body, including those that work the jaws. I certainly haven’t seen this on any ATP tour players.

Sure, there will be certain players who will break the rules by using banned substances. In tennis, breaking the rules probably means using illegal amphetamines to give that little extra concentration boost, or using other chemicals to speed recovery between matches. Steroids would be far from the top of the list.

As for certain female players like Maruesmo and the Williams sisters, their muscle can be easily explained by natural testosterone levels. Everyone, male and female, has testosterone naturally occurring in their bodies. Men, of course, have much higher levels because their testes are constantly producing the substance. But females have naturally occurring testosterone in their bodies as well, and some have higher levels than others. Maruesmo and the Williams sisters definitely have higher-than-average levels of testosterone, but their muscle mass falls well within the normal range for professional athletes.