Burnout sets are a classic strategy to maximize fatigue and muscle stimulation, however, they can get boring. If youíre looking for a new way to maximize fatigue and stimulation, give cluster sets a shot. Start with a weight around your 15 rep max and perform 5-8 reps, rest for 10-15 seconds, and repeat for 3-4 minutes. The first few clusters will be easy, but once youíre a minute or two in it gets really fun. Try these on isolation movements or machines for best effects Ė compound free weight movements will probably be too taxing to go much longer than 1-2 minutes.