Eric Roberts breaks down a study comparing rest periods between sets: lifters who rested 90 or 180 seconds built roughly double the muscle in their quads and biceps compared to those resting just 60 seconds. Short rests tank your strength on later sets, forcing you to lift lighter and lose the mechanical tension that actually builds muscle.
Does how long you rest really make a difference in your progress? The answer is yes, and it's a lot more than you think. There was a study that took three groups of people: one rested sixty seconds, one rested ninety seconds, and one rested a hundred and eighty seconds. In both Their quads. And biceps. Their muscle growth doubled when they rested 90 or 180 seconds. But why does resting longer mean more muscle growth? Because when you rest less than 90 seconds, the fatigue from your previous set prevents your muscles from fully recovering. So on sets 2, 3, and 4, your strength and the amount of reps you can do fall off a cliff, which means you'll have to lift lighter weight for less reps. And because you lift less total weight over the course of a workout, which means there's less mechanical tension on your muscle, which is the main driver of muscle growth. So use this as your sign to start being lazy in the gym.
