The claimEvidence C · limited
Stretching more will build muscle
The evidence
A small effect shows up only with long daily stretching for weeks; a few minutes before or after training will not grow muscle.
Why the claim spreads
It borrows a real lead: training a muscle in its lengthened position can grow some two-joint muscles more, and stretching adds a passive tension inside the muscle. From there, 'stretching alone builds muscle' sounds like one small step.
The mechanism, in brief
The same muscle can grow by different amounts depending on the position you train it in. The difference lies in how it is loaded when it is stretched long.
Sources (5)
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- Kinoshita, M., Maeo, S., Kobayashi, Y., Eihara, Y., Ono, M., Sato, M., Sugiyama, T., Kanehisa, H., & Isaka, T. (2023). Triceps surae muscle hypertrophy is greater after standing versus seated calf-raise training. Frontiers in Physiology, 14, 1272106.
- Gordon, A. M., Huxley, A. F., & Julian, F. J. (1966). The variation in isometric tension with sarcomere length in vertebrate muscle fibres. The Journal of Physiology, 184(1), 170–192.
- Wolf, M., Androulakis Korakakis, P., Piñero, A., Mohan, A. E., Hermann, T., Augustin, F., Sapuppo, M., Lin, B., Coleman, M., Burke, R., Nippard, J., Swinton, P. A., & Schoenfeld, B. J. (2025). Lengthened partial repetitions elicit similar muscular adaptations as full range of motion repetitions during resistance training in trained individuals. PeerJ, 13, e18904.
- Plotkin, D. L., Tiede, D. R., Gotla, T., Kelly, J., Rollin, M., Queneau, J., Wilborn, C. D., Meyer-Vega, M., Robles-Cerdas, V., Bashir, A., Beyers, R. J., Esquivel, C., Kontos, G. J., Mobley, C. B., Babl, R., Kavazis, A. N., Beck, D. T., Baweja, H. S., Vann, C. G., ... Roberts, M. D. (2026). Acute Molecular and Chronic Vastus Lateralis Adaptations to Lengthened Partial versus Full Range of Motion Resistance Training in Trained Men. Medicine & Science in Sports & Exercise.