Stretch-Mediated Hypertrophy: The "Free Gains" You Are Missing
New research confirms that the 'stretched position' is the most anabolic part of the rep. Here's how to program 'Long Length Partials' for your hypertrophy clients.
We have all seen “ego lifting”—the guy on the leg press moving the sled four inches. We mock it because it’s lazy.
But biomechanics is funny. It turns out, if he was doing the bottom four inches, he might have been smarter than the guy locking it out.
Stretch-Mediated Hypertrophy is the biggest shift in bodybuilding science in the last decade. The data is now conclusive: Muscle grows best when challenged at long muscle lengths.
The Science: Why the “Squeeze” is so Overrated
For years, we cued “squeeze at the top!” (Peak Contraction). The 2024 systematic review by Wolf et al. flipped this.
- Short Lengths (The Squeeze): Low mechanical tension. Low muscle damage. Low growth signal.
- Long Lengths (The Stretch): Massive mechanical tension. High passive tension from the titin filament. Maximal growth signal.
In head-to-head studies (Pedrosa et al.), doing only the bottom half of a rep (lengthened partials) often outperformed full ROM.
The Protocol: “Long Length” Programming
You don’t need to have your clients do half-reps. But you do need to stop letting them cut the bottom.
1. The “Pause” Prescription
The easiest way to force stretch-mediated growth? Pause at the bottom.
- Squats: 1-second pause in the hole.
- Bench: 1-second pause on the chest.
- RDLs: 2-second pause at the bottom. This kills the “bounce” (elastic energy) and forces the muscle fibers to bear the load in their most vulnerable (and anabolic) position.
2. Exercise Selection
Swap “Short Length” movements for “Long Length” ones.
- Hamstrings: Seated Leg Curl > Lying Leg Curl (Seated puts the hamstrings in a greater stretch at the hip).
- Triceps: Overhead Extensions > Pressdowns (Overhead stretches the long head).
- Glutes: Deep Split Squats > Glute Bridges (Bridges load the short position; Squats load the stretch).
The Warning: Manage the Damage
Training at long lengths causes significantly more muscle damage (micro-tearing). Your clients will be more sore. If you switch a client to a “stretch-focused” block, reduce the volume. They cannot handle 20 sets of deep, paused RDLs. Start with 8-10 high-quality sets.
The Bottom Line: Don’t waste energy on the lockout. The gains are in the pain cave at the bottom. Live there.
Primary Sources
- Warneke, K., et al. (2024). Effects of Chronic Static Stretching on Maximal Strength and Muscle Hypertrophy: A Systematic Review and Meta-Analysis. Sports Medicine - Open.
- Pedrosa, G.F., et al. (2023). Partial range of motion training elicits favorable improvements in muscular adaptations when performed at long muscle lengths. European Journal of Sport Science.
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