If he's actively pushing himself backwards then you need another frame where the toes touch the ground but the body travels backwards - this is the frame where he actually does the pushing
to do follow through animation you need to not mirror the animation but delay it. This can be tricky to think about, but just try to imagine it. Make the hair stand still when he starts to move, then move the hair the same amount as he moves, then make it continue moving when he stops, then paint the little rebound. At that point some things will look right and others will look a bit off. Try to localize the off parts and make them make more sense. And then you're done! That's how I do it.
Also yeah, think about that leg breaking and make sure they .. don't
also on the same topic I do think some redrawing is in order. Since his hand remains on his hip it doesn't change, but the arm probaby moves a pixel or two when his back extends and retracts (which isn't actually possible, but since the bend of the spine that accomplishes this is so subtle just extending and retracting is ok by my standards!) Make sure that some distances stay the same - distance between shoulder and elbow, elbow and hand. Then if they change lengths, instead change, for example, the elbow's position to make sure they stay the same. Then repaint.
Stuff like that.
Also your style of pixels, shading and character design right now are scarily close to my own.
Of course I love it * U * <3