Saw an interesting clip of Lomachenko training his hand eye coordination with a tennisball attached to a base ball cap. Made myself one a couple hours ago, and tried it. I love it! You get a great warm up for starters to go on to some heavier stuff, and get a fenomenal focus because your so concentraded on that little ball. You can work on a variety of stuff doing this drill: punching while moving, pivoting, blocking/parrying/slipping and work on your handspeed and coordination. Love it! http://rosstraining.com/blog/2012/01/11/tennis-ball-reaction-training/ http://rosstraining.com/blog/2012/01/23/tennis-ball-reaction-training-part-2/
Kostya Tszyu used to do something similar, Bep. I remembered watching footage of it. It helps training for elusive, unpredictable boxers---teaching one when to wait and when to punch.
And, lets face it, its fun hitting stuff, anything really. Wheter its a ball, bag, glove, ribcage or a face or in this case a tennisball. Its easy to get discouraged though when you first start out with the tennisball, takes time to get the hang of it.