You might want to lean his body forward a little, that would give the animation some energy.
As for the arms, the latest version looks as if he is working out, like stretching his waist or something. This one -
- isn't so bad, really. If you make him throw his arms forwards instead of upwards, that might look even better.
There's also a problem with legs. I tried to fix it for you. Not perfect, but I think you'll see what I mean.
Or you could keep things basically as they are. This animation looks comic, and if that's what you're going for it, then you've succeded:-)
P.S. Shading the farther leg would be a good idea, too, I guess.