All of the important stuff is in the top half and there's nothing of any note in the bottom to anchor it.
I gotta say, I think that works here. Cropping anything off the bottom makes it too tight and changes the image for the worse imo.
I didn't think that cropping the bottom would help.
I think that if more of the swing, particularly the other leg, were shown, then the impression of swinging up away from an earth-bound object would be stronger.