[kuri]

faster = more powerful punch

Patricia, your right on about punching power coming from the legs/hips.

Bruce Lee weighed what... 140lbs? He probably wasn't benching 260, but we all know his mastery of the mechanics of punching + speed resulted in some hellacious power.
In fact his training logs I've seen never had him doing less than 10 reps of anything.

Maybe Ko can address this but I haven't seen that many of the top MMA guys do any low rep training. Chuck Lidell & Fedor probably have the most devastating punching power but what I've seen of their training is geared more towards muscular endurance. Lidell, as well as BJ Penn reportedly do alot of Crossfit-type metabolic training, aside from heavybag work of course. What I've seen of Fedor's training involves kettlebells, sledgehammer on a tire, and shadowboxing while holding those little iron bars.