Sometimes when I watch olympic lifters on ESPN.... their attempts look maximal effort...... I dont know about their training but they probably never max out on clean and jerk, and snatch.... just like powerlifters. Only on the contest day they try out their maxes. That may be the reason why their knees cave in, their snatch lockout is uneven and other things. All of this is because they are pushing their limits and the weaker links break down. However I see no purpose why this has to happen in training.. just an opinion.