Those who follow me at rosstraining have likely read some of my posts about hand-eye coordination. One drill that I’ve referenced before is to strike a tennis ball that’s attached to a hat with an elastic cord (ex. here). The drill has become quite popular in recent years. World champion Vasyl Lomachenko is one boxer who is often seen using a similar device. Many actually believe that he is the first boxer to use such a tool. The reality though is that Kostya Tszyu was training with a reaction ball long before Lomachenko became a household name.