Is Gain Tape Helpful for Tennis Players?

A lot of it is because it's physical and its external. A good camera on the side lines, then we can watch the tape and slow it down to make sure they're moving in just the right way. And likewise, with piano, it my vid, my hands all sometimes notice ai really, i'm playing with only with my fingers. It's like a bad thing to do. And i need to be playing ik with my whole arm and my elbowd my wrist and my body.