Pre sickness Lesnar was a better athlete, faster, stronger even bigger and bonus a lot more confident the way he shoot double legs was totally different after the surgery.
People that recover from having having 12 inch section of there colon removed will testify there not the same.. the intake, there athleticism, heck there day to day lives will be changed / affected when you add this to a 285+ lbs HW MMA fighter and not to a regular joe not doing anything extreme, it takes away from preparation, diet, how hard you can work and push yourself and doubt will creep into the back of your mind.