I totally agree with his view. Although I’ve made the mistake of overusing some part of my body (usually the shoulders) by focusing too much on one thing, which can be hard to avoid when you’re trying to improve or achieve a goal in a specific sport.
Judo, inline skating, parkour, BJJ, wrestling, gymnastics… what else should I do? I reckon I should probably swim more often. I ride my bike nearly everyday, so cycling should be covered.