A handful of studies have demonstrated that workouts consisting of 1 set per exercise performed 2–3 times per week can significantly increase muscle size and strength,[1][2] albeit the increase is less than it would be if more work was performed, especially in the context of muscle gain. According to a 2017 meta-analysis, performing <5 sets per muscle group per week produced muscle gain, but the percentage increase (5.4%) was less than that of 5–9 sets (6.6%) and 10+ (9.8%) sets per week.[3]
Even those with a bit of resistance training experience under their belt can make meaningful — but suboptimal — progress with a relatively low dose of exercise. According to a meta-analysis published in 2020,[4] performing a single set of 6–12 repetitions to failure with a load of 70%–85% of 1-repetition maximum (1RM) two to three times per week for 8–12 weeks can increase squat and bench press 1RM by about 17.5 and 8.25 kilograms, respectively, in individuals with at least one year of training experience.
There is also evidence in powerlifters demonstrating that relatively small amounts of work can significantly increase strength. According to a study consisting of multiple experiments published in 2021,[5] a program with the following characteristics can promote meaningful increases in 1RM strength on the powerlifts (i.e., the barbell back squat, bench press, and deadlift) over 6–12 weeks:
- Volume: 3–6 sets of 1–5 repetitions per week
- Load: ≥ 80% of 1RM
- Frequency: 1–3 sessions per week
- Proximity to failure: 1–4 repetitions shy of failure
Some people may be okay with doing the bare-bones amount of resistance exercise necessary to make some semblance of progress in muscle size and strength, but what about those with more serious goals? Are they doomed to suboptimal gains due to their lack of time? Not necessarily.
There are ways to structure a workout to reduce the amount of time spent in the gym without leaving gains on the table. One strategy is to perform supersets (i.e., sets of two exercises performed in succession, with limited to no rest between them) involving exercises for agonist and antagonist muscles. For example, one study had participants perform the bench press and bench pull (a row) exercises.[6] For 8 weeks, one group took 4 minutes of rest between each set of both exercises, while the other group took 4 minutes of rest between supersets, which resulted in the workouts taking approximately half the time. In the end, increases in 1RM were similar between groups for both exercises.
Another strategy is to perform rest-pause sets, which involves performing a set to failure, taking a brief rest (typically 20 seconds), and repeating this cycle until a prespecified number of total repetitions is completed. In a 6-week study, the traditional group performed each exercise for 3 sets of 6 repetitions using 80% of 1RM and rested 2–3 minutes between sets, while the rest-pause group performed an initial set with 80% of 1RM until failure, rested for 20 seconds, and repeated this cycle until they completed a total of 18 repetitions.[7] This resulted in the training sessions lasting around 57 and 35 minutes in the traditional and rest-pause groups, respectively.
In the end, increases in 1RM strength did not differ between groups, while the increase in thigh muscle thickness (but not arm or chest thickness) was greater in the rest-pause group. However, this difference was likely due to the fact that the rest-pause group exerted a greater degree of effort during their workouts, as a set of 6 repetitions with 80% of 1RM typically means ending the set a few repetitions shy of muscular failure, and as stated in “Do I need to train to muscular failure?”, there is an advantage to training to failure for muscle gain.