Of course training the legs is important.

My post, however, was designed to point out that the training of the legs is different depending on what you want to accomplish. What builds muscle will not always build power and speed - the kind you need to jump higher.

For one thing, it has to do with motor units and muscle fiber recruitment. Sprinters, for instance, have huge legs but they don't get them from squatting. It comes from fast explosive movements that build up the fast twitch fibers, expecially the 2B's. I'm not saying they don't train their legs, they just don't do it to only build muscle.

The power and speed you need to run fast or jump high comes also from the CNS's ability to recruit the maximum number of muscle fibers as quickly as possible - perhaps all at the same time. Much like a powerlifter. Traditional bodybuilding practice recruits fiber in an incremental fashion.

The advice needs to be tailored to an individual's needs in his or her sports. If someone uses incorrect parameters in his or her leg training, they may find their speed and jumping ability decreasing.