Following rest intervals may be the most overlooked aspect of any training program, yet it is really important in helping you reach your goals. In other words, pay attention to the clock when you rest, not the girl in the tight spandex doing Romanian Deadlifts. Again, rest intervals depend on the training phase you are in. For maximal strength and power, rest should be longer—around 2 minutes between sets as you really want to feel recovered in between sets. For size, 45 to 75 seconds between sets is a good rule of thumb. Metabolic training relies on your heart rate being elevated so you don’t want rest to be too long, 30 seconds or less.