Speeding through your sets could be a sign you're depending on momentum, doing the exercise incorrectly or using too much or too little weight. With any strength move, go at a slow, controlled pace: two seconds up, two seconds down. "There should be no point at which you pick up speed," says California trainer Jay Blahnik, the author of Full-Body Flexibility. He recommends this slow-down trick: While doing lunges, place your front foot on a Bosu Balance Trainer. The instability forces most people to focus more intently to avoid slipping.
Read more: Rework your workout