Art critique and advice; beginner artists are welcome to post here; includes an oekaki. (NO FLAMES)
Artists, read before posting!
Before you post your art to ask for critique, please read these tutorials. They explain the basic principles of drawing and figure drawing. Most posts where these basics are missing will never get a response, as people are quite frankly sick and bored of explaining over and over that you would have to pretty much learn how to draw first, before you could improve.
I don't see much wrong with your legs. Besides some parts being to long or thin, they look fine. You also need to draw the left leg, but I think you already know that.
What I can say you need work on is proportion and foreshortening. The angle you have him at doesn't stay true to the way you drew his muscles. Meaning if he were to face you, he would have uneven sized muscles, and they'd be at an upward slope.