Can maintain 95-100% VO2max for ~ 5 min Power/force drop ~40-60% during 30s all-out ex Causes of fatigue Lactate, H+ (questionable) Ca transport slow, reduction in Ca re-uptake by SR (肌 漿網) Excitation-coupling failure, reduced nervous drive at spinal level In repeated bouts, incomplete PCr resynthesis during recovery between successive bouts