
It has to be the smallest space between ball and ground considering a foot, but...

here's the ball is as close to the ground as a foot has no space to be between ball and ground, and... The foot has such that ball can only bounce after concacting it (but foot would have the straight position as after tb), but...

finally, how could it be that we saw a foot beside the ball? o.O You can see the trace of foot and it obviously shows us that. One more, you would have never done skatw having that position of foot right after performing it.