I have a woman's legs.

http://www.youtube.com/watch?v=1gHsQoqQPd4&cc=1#t=115s

One of the unfortunate physical non-ailments I lament at length is that I am slightly knock-kneed, particularly with my knees bent at all. This means (as for many people) that my ITBs (iliotibial band - the band of muscle and adjoining tendon on the outside of your leg) get exercised whenever I bend my legs, straighten my legs or clench my leg muscles. The VMO (vastus medis oblongatus - the muscle that bulges on the inside front above your kneecap when you straighten your leg to its limits) is not exercised very much.  Furthermore, the odd angle through my knee means that all kinds of odd torques need to be reacted up through my thigh and into my hip - a straighter leg would reduce these.

But don't waste too much sympathy - my legs are a little bendier than the ideal man's, but they are much less bendy than those of most women, who having broader hips, tend to have a bend at the knee.  What has really stymied me as a runner is my horror of effort without the promise of world-championship (which is a pretty broadly applicable horror given my lack of any genius).

I wanted to link to video from Parks and Recreation, a scene from the basketball game in season three, where Ron Swanson asks Tom Haverford 'Are those women's sneakers?'
Tom replies 'They fit real well and I like the styles.  Also I got a discount when I was working at Athlete's Foot.  And the best part is, no one can tell.'