It is well established that lifting loads around 75% of your 1RM leads to increases in size and strength. More recently it has been shown that lifting much lighter loads (30% 1RM) also leads to significant muscle growth if each set is taken to failure. Metabolic stress is a primary stimulus when using low loads to failure. Strength gains using low loads, however, are much smaller than when using heavy loads, even when taking all sets to failure. Dropsets involve performing a set to failure with a given heavy load and then immediately reducing the load and continuing to train until you reach failure again. A dropset may involve reducing the weight once or multiple times. It’s possible that dropsets, which involve both heavy and light loads, are an efficient way of building both size and strength.
Researchers tested the idea that a single dropset of biceps curls might be as effective as multiple heavy or light sets taken to failure in developing strength and size respectively. Untrained subjects were assigned to one of three training conditions: three sets of high-load (80% 1RM) curls taken to failure, three sets of low-load (30% 1RM) curls taken to failure, or a single high-load (80% 1RM) dropset of curls with four descending increments at 65%, 50%, 40%, and 30% 1RM without rest between sets.
There was a significant increase in muscle size in all three groups, with no differences between groups. Strength, however, significantly increased only in the 80% 1RM and dropset groups.
A single dropset starting with 80% 1RM performed with four descending weight increments was as effective as three sets to failure using 80% 1RM and three sets to failure using 30% 1RM for developing muscle size of the biceps. A single dropset was more effective at developing strength than three sets to failure using 30% 1RM but less effective than three sets to failure using 80% 1RM.
Although this study used untrained subjects, it shows that a single dropset taken to failure is an effective way to train. When days come up where you’re pressed for time and debating whether to go to the gym, know that you can do single dropsets for each muscle group you train that day and get growth stimulus.