I had 56 amateur fights and can only remember two or three when I was 'perfect'. Every other bout was with me carrying an injury or having some sort of niggle.

If you're training hard for a fight, or a tournament, you put your body under tremendous stress and pressure, plus you're doing hard sparring. Injuries are statistically very likely.

I always assessed things by 1) how much the injury will affect my performance and therefore the risk of losing and 2) if it was a latent injury, like a bad back or whiplash, how likely is it to flare up during the bout.

I pulled out of one fight because of those assessments.

The real reason Rocky Marciano retired was that he was carrying a latent back injury, and by the end of his career it could have 'gone' at any time in the ring.