Has anyone heard of this basketball exercise?

I was watching a TV episode of some crime, Law and Order, and they had a case with a ball player. One of the ball players had his arm in one of those cottom materials whi u use to hold ur broken hand to a 90 DEG angle.
The cop guy said there was nothing wrong with his hand and that is was a execise ball players do for they off hand?
Not sure what he said y they do it. Does any1 kow anyting sbout it?