Probably weightlifting related. As I see that Peter bulked up to 270 lbs. Why is the hell would Sam Peter be 46 years old? I remember HBO remaking that Peter was a young upcoming HW of 25 years old when he fought Klitschko.
At least Peter is not 36 . I remember the story that supposedly 16 y.o. Peter sparred with 24 y.o. Ike Ibeabuchi who just beat David Tua. Imagine that amateur teenager sparring vs young top HW pro who just beat another top-10 undefeated contender in Tua.
Ask yourself why Pulev wasn't moving around the ring like that against Wlad? The answer is in the canvas. Wlad cheated Pulev with the illegal bouncy castle ring. He never really lost