Should you really slow down your reps in the gym for muscle growth? Does it really matter how long each rep lasts? You might have heard gym buffs and bodybuilders talking about slowing down those reps and focusing on control and technique rather than speed. From time under tension (TUT) to tempo and eccentric training, these are frequent hot topics in the world of bodybuilding and fitness.
In an interesting study, researchers explored how tempo affects hypertrophy (muscle growth), and it turns out it doesn’t matter as much as we thought. Let’s check out the research.
The study
In a meta-analysis published in the Journal of Strength and Conditioning Research, researchers examined 14 high-quality studies to assess how the concentric and eccentric phases of an exercise affected muscle growth and how muscles responded to time-under-tension. Does lifting weights slowly or quickly build more muscle? In these 14 studies, the only factor that changed was the speed of the repetitions, but the weight, sets, rest, and everything else stayed the same.
The study authors compared:
- Slower reps: Averaged around 3.5 seconds per rep. (Ranging between 1.7 and 4.5 seconds).
- Faster reps: Averaged around 1 second per rep. (Ranging between 0.3 and 2 seconds).
The results
Here are the results:
- Slow and fast reps both yielded the same amount of muscle, with no meaningful difference in muscle growth between the two.
- The speed of your reps doesn’t have a major influence on muscle growth.
The study authors also assessed differences between eccentric-only, concentric-only, upper vs. lower body, and training to failure vs. not training to failure. The results showed that the differences in muscle growth among these were tiny or uncertain. Overall, research shows that concentric-only training isn’t as favorable for promoting muscle growth compared to concentric-eccentric training.
Concluding thoughts
The researchers concluded that you don’t need to rush or really slow down when weightlifting to build muscle because it makes a minimal difference, at least according to this meta-analysis. It’s better to focus on training consistently, training close to fatigue, incorporating progressive overload, and using the right weight. It’s also best to make sure you’re powering through enough sets per muscle group.
Maybe sometimes we’re overthinking it in the gym. Instead of focusing so much on the speed of your reps, the researchers concluded that it’s better to shift your focus to efficiency and safety. Go with what feels right and more comfortable for you, for safety, efficiency, and technique, rather than worrying so much about the exact number of seconds you’re holding each rep.
