Eye hand coordination is a big part of being a great ball handler. Partner tennis ball drills require you to put your focus on the tennis balls instead of dribbling the basketball. The idea behind this tennis ball drill is to teach you to be able to dribble a basketball without having to think about it. Another great thing that this drill does is it improves your reaction time. You have to cross the basketball over as soon as you see the tennis ball coming at you.
