The boxer Vasyl Lomachenko trains with a tennis ball hooked to his cap by an elastic. This simple exercise that does not require a lot of material, just an elastic, a tennis ball and a cap, allows him to work and improve his ccoordination and his reflexes. Vasyl Lomachenko is a 29-year-old Ukrainian boxer. He was Olympic champion at the London Games in 2012 (light weight) and world champion Weight Feathers WBO (2014-2016).