Smooth Animation

This may be simple, but please help me out. I’ve been animating a fight sequence, and my animation is not being smooth. If you would like to see what I mean, here is the file, but before you look at it, the problem only starts at frame 250, ignore the rest ( When you look at the file you will see what I mean. When the monkey character moves, the first movement of his legs is meant to be smooth, but it slows and starts again where the keyframe is, how would I change this?

Hungry Computer