Can you build stronger hamstrings by just holding still?
Effects of Low-Intensity Torque-Matched Isometric Training at Long and Short Muscle Lengths of the Hamstrings on Muscle Strength and Hypertrophy: A Randomized Controlled Study
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
People did short, low-effort leg holds twice a week for two months, either with knees bent a little or a lot. Even though their muscles didn't push as hard when bent a little, both groups got stronger and their muscles grew a bit.
Surprising Findings
Muscle growth occurred even when active torque was significantly lower in the long-length group (30° knee flexion) compared to the short-length group (90°).
Common belief: more force = more growth. But here, less muscle force led to equal hypertrophy — suggesting mechanical tension isn't the only driver.
Practical Takeaways
Do 5-second isometric hamstring holds 3x/week at your target knee angle (e.g., 90° for squat strength) using 30% of your max effort — no equipment needed.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
People did short, low-effort leg holds twice a week for two months, either with knees bent a little or a lot. Even though their muscles didn't push as hard when bent a little, both groups got stronger and their muscles grew a bit.
Surprising Findings
Muscle growth occurred even when active torque was significantly lower in the long-length group (30° knee flexion) compared to the short-length group (90°).
Common belief: more force = more growth. But here, less muscle force led to equal hypertrophy — suggesting mechanical tension isn't the only driver.
Practical Takeaways
Do 5-second isometric hamstring holds 3x/week at your target knee angle (e.g., 90° for squat strength) using 30% of your max effort — no equipment needed.
Publication
Journal
Journal of Strength and Conditioning Research
Year
2023
Authors
Sayaka Nakao, T. Ikezoe, M. Taniguchi, Yoshiki Motomura, Tetsuya Hirono, Shusuke Nojiri, Remi Hayashi, Hiroki Tanaka, N. Ichihashi
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Claims (4)
Even if you're not pushing very hard, doing short muscle holds at different knee angles for eight weeks can make your hamstring muscles bigger and stronger, no matter if your knee is mostly bent or almost straight.
If you do hamstring holds with your knee almost fully bent, you might get stronger at that angle more than if you do the same exercise with your knee only slightly bent—even if you're pushing with the same total force.
Even though people push with the same total force during hamstring holds whether their knee is bent or straight, their muscles are actually working less hard when the knee is more bent.
Isometric contractions performed at longer muscle lengths produce greater muscle hypertrophy than isometric contractions performed at shorter muscle lengths.