Try alternating between high repetition workouts with low repetition workouts. For example, when training on squats, try sets of 18, 24, 30, and 36 reps for 3 weeks. Then, do sets of 6,8,10, and 12 for another 3 weeks. This keeps your muscle on their “toes”, or confused, allowing for optimal development . Also, this method helps many people through plateaus.