Actually the Romans were the second but they claim to be the first. Pricks.

Relentless, it is know that there is mroe than one type of muscle fiber and each works differently. All complex training is doing is argeting both by doing the exercizes that engage that fiber. Do one set at heavier weight for max strength and one set at lighter weight for speed strength. You must always keep your movements "fast" though. The faster the movement, the more the fast twitch muscles angage, even at heavier loads. People think wieght training as wrong for boxing. That in itself is wrong. The secret is selected and diverse weight training.

Read about explosive lifting.