It's the timing aspect, and it's particularly an issue with squats. Even at lower weight, it's far to easy to get your knees pushed forward or your back arched

It's the timing aspect, and it's particularly an issue with squats. Even at lower weight, it's far to easy to get your knees pushed forward or your back arched when trying to pump through them as fast as possible. I don't think anyone is saying that it's not possible, it's just much more likely that your average lifter is going to run into injury.