Training harder very rarely results in improved power or speed. That's great but there are plenty of other examples where a fighter has looked rejuvenated after working with a strength and conditioning coach i.e. Hopkins vs Tarver. Also just because a fighter has a new strength coach doesn't mean that it's going to be perfect or it's going to compensate for boxing skills. Marquez already had all the boxing skills in the world, he'd never knocked Pac down before. The training he's been doing allowed him to knock Pac down and out. The knockout was more a perfectly timed/placed punch that Pac didn't see but the first knockdown showed the brute force Marquez brought into the ring this time. Calzaghe is a guy who could've really benefitted from a good strength and conditioning coach. Great boxer but no explosion, just a tough endurance fighter who slapped a lot. I don't think his chin was anywhere near granite either. Valero we'll never know about because he didn't reach the A grade opponents.