It's a good drawing and the animation looks quite organic, but too fast. The legs make it look like he's going at a pretty brisk pace, not a jog or a spriting pace, but a very brisk walk. If that's the way you wanted it, then the legs are fine as they are if you ask me, BUT something needs to be done about those arms. They're going very fast. Try making them move slower as they get nearer to the top of their swing arc, or just put a delay on the frame in which the arms are at the peak of their swing.
Pretty good overall though.
Pretty good overall though.