For Pacquiao, yes he has Alex Ariza which is an extremely smart move and why many British fighters suck because they have old school trainers who tell them "weights will make you slow" - Absolute bullshit. Why do Khan and Macklin look so much more explosive now?

But for Mayweather..hmm, I'm not sure..his strength and conditioning coach is Leonard Ellerbe. I imagine the most he knows about "weight training" is gorging on pork pies. (I guess he can get a little bicep curl going)

The most I've seen Mayweather do with weights is punching with dumbells. Hardly explosive weight training. I think he is too stubborn to give money to anybody outside of his camp so just pays Leonard to hold his feet while his does situps and count punches on a counter.

Good theory - but you need to remember, Cotto is another of the smart ones that has a strength and conditioning coach who featured throughout his camp with Pacquiao.

I think people mistakenly correlate weights = muscle.

Not so, you can still do weights and not put on any muscle. For example, Mosley could still do weights if he's trying to make weight to keep his power. The fact that he would be on a low calorie diet means that HE WOULD NOT put on any muscle. You can do weights until you're blue in the face but if you aren't feeding the muscles after they've been damaged, they ain't growing!

Also, how many people do you see who go to your gym and NEVER look any different? 95% of the membership base? You might see them working their ass of but their diet SUCKS - Muscles do not grow without the calories and protein just like a car does not drive without fuel