Good example currently being Cotto and Coach Roach, Roach a guy who carries a lot of reputation with him and Cotto a seasoned pro in the twilight of his career. How much influence do you think a certain trainer has on a guy who is say 25-2 when they've been trained by a couple different trainers and been through many intense camps and basically have a certain style which is now innate to them at this point. Examples such as Hatton trying to switch to Floyd Sr late in his career and doing Mayweather type padwork, I can't help but think something like that has very little impact. What was the real effect of Groves switching camp from Booth to Fitzpatrick for the Froch bouts, with many people suggesting he should go back to Booth? How much of Cottos win was down to the new training camp of Roach and how much of it was down to Martinez just being too past prime. Then you have guys like Floyd Mayweather Jr, where I genuinely believe that if neither Floyd Sr or Roger turned up for the entire training camp it would make not a jot of difference. So ... Can't teach an old dog new tricks or Always room for improvement?
I dont think you can teach a fighter like Cotto new things. What you can do is re-motivate them and make sure the skills they do have are sharp, and that you get them fighting to their strengths.
It's hard to say unless you're a professional boxer. I guess we have to take their word when they say a new trainer has helped them. Unless it's a placebo effect.
Depends... Some fighters need that "Father figure" in their corner more than they need actual personal trainers. Motivation & confidence go a long way.
That's probably a lot to do with what makes Freddie Roach a great trainer, I've heard Roach say things in the corner to Pacquiao like "don't let him 'fking touch you son", there does appears to be a father-like aura about him.