How Many Sets for Muscle Growth? (New Study)

Although research suggests higher sets generally lead to greater hypertrophy, the video stresses that this doesn't mean everyone needs to train with extremely high volumes. Diminishing returns exist, and respectable gains can be made with lower volumes. There's also greater uncertainty with very high set numbers due to limited research. Long-term studies show an even stronger relationship between sets and hypertrophy, further countering the swelling argument. Ultimately, individual situations, preferences, and the ability to maintain high effort are key. The video recommends training as much as one can handle with high effort, adjusting over time, and potentially specializing in a few muscle groups with higher volumes, gradually easing in.

A 2023 study involving 31 trained individuals explored the impact of varying set volumes on leg muscle growth. Participants performed 22, 42, or 52 weekly sets, progressively adding sets over time. The study found that higher volumes, up to 52 sets per week, led to greater muscle growth and strength increases, challenging previous assumptions about volume thresholds. However, critics questioned if the increased size was true hypertrophy or transient muscle swelling, as measurements were taken 72 hours post-workout.

A meta-regression combining data from 35 studies further suggested a linear relationship between sets and hypertrophy, with no plateau. This fueled skepticism that muscle swelling, often detectable 48-72 hours after exercise, could be artificially inflating muscle size measurements in higher volume protocols. The lack of studies directly comparing swelling responses across different set numbers left this argument unresolved.

A new study, the first to directly investigate muscle swelling in response to varying set numbers, recruited 13 trained individuals who performed 7, 14, or 21 total sets in separate workouts. Muscle thickness was measured immediately, at 24, 48, and 72 hours post-workout. Surprisingly, the study found no significant differences in swelling responses between the different set volumes, and swelling had largely subsided within 24 hours for all conditions. This suggests that muscle swelling is unlikely to be a major confounding factor in hypertrophy assessments when measurements are taken 24 hours or more after training.

The video emphasizes the 'repeated bout effect,' where the body adapts to consistent training over weeks, leading to reduced muscle damage, fatigue, and swelling. This means that swelling observed after a single workout may not be representative of the long-term swelling responses in a prolonged training program. Studies show progressive reductions in damage indicators with repeated training, reinforcing the idea that swelling is less of a concern in long-term hypertrophy studies.

While the meta-regression initially suggested strength gains plateau at around five sets per muscle group a week, leading to further skepticism about high-volume hypertrophy, a more focused analysis on studies involving trained individuals with related strength and size measurements reveals a different picture. When considering these specific studies, higher sets generally correlated with both greater size and strength increases, suggesting that the hypertrophy observed is indeed 'real' and accompanied by functional improvements.