I will start with this classic expression. 'On the ball' means alert, in control, effective. Mugen kids love to warm up with the work out ball before practice starts. They use it for balance and control. As when doing karate, so much has to do with control and balance. Very similar in the adults class, we do 'the balance game' whereby we stand on the balls of our feet to then see if we can knock over our opponents by pushing them with out hands. Balance & Control is such an important aspect of Karate. Especially for the Mugen style, it is probably more important than being physically stronger and more powerful.