The Study
Loaded inter-set stretch may selectively enhance muscular adaptations of the plantar flexors
This study is like a science experiment where one leg of each person did a normal workout and the other leg did a workout with extra stretching in between. Because they compared the two legs of the same people, it's a good way to see if the stretching actually helps muscles grow. However, because they only tested a small group of young men who don't usually lift weights, we can't be 100% sure it would work the same way for everyone else.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Researchers tested if adding a 20-second weighted stretch between calf exercise sets helps muscles grow more than just resting normally.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 560 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The size increase is small but statistically meaningful for beginners, and the strength gain is practical for daily movement, though it does not replace standard training volume.
- 2After 8 weeks, the stretching leg gained 0.7 mm more deep calf muscle and 6-7 Nm more strength.
- 3The outer calf muscles showed unclear growth differences, and the outer calf naturally grew more than the deep calf overall.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
PLoS ONE
Year
2022
Authors
Derrick W Van Every, Max Coleman, A. Rosa, Hugo Zambrano, Daniel L Plotkin, Xavier Torres, M. Mercado, E. D. De Souza, Andrew Alto, D. Oberlin, A. Vigotsky, B. Schoenfeld
Related Content
Claims (6)
If you swap out your usual rest breaks between weightlifting sets for stretches that include light weights, this claim says it will help your calf muscle grow bigger and get stronger. It suggests that active stretching beats just sitting still when trying to build calf size and power.
Adding a short, weighted stretch between your workout sets can make your calf muscles grow bigger over two months. This happens because the stretch keeps the muscle working longer, which helps it build more size than just resting normally.
Adding short, weighted stretches between your weightlifting sets won't actually make your calf muscles grow bigger in young men who don't train regularly. The tiny changes you might see are just normal measurement noise, not real muscle growth.
Adding a short, weighted stretch between your workout sets can actually help your calf muscles get a little stronger over two months. This extra stretching boosts your muscle power without slowing down your regular strength training progress.
After eight weeks of leg workouts, the outer calf muscle grows noticeably bigger than the inner calf muscles in beginners. This suggests that muscles made up of faster-twitch fibers are naturally better at getting bigger when you first start training.
If you add a quick 20-second stretch with some weight between your sets of leg exercises, you might build bigger calf muscles without making your workout longer. This works because you're stretching during your normal rest time, so it's a quick way to get more out of your training.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.