- Aug 14, 2018
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One of the more interesting shifts in hypertrophy research over the last few years is the attention on where in the range of motion the muscle is loaded — specifically, whether training at long muscle lengths (the stretched position) produces extra growth compared with training at short lengths or through a standard full range.
The signal started with studies on exercises like overhead extensions versus pushdowns for the triceps, and preacher versus incline curls for the biceps, where the long-length condition grew more. Pedrosa and colleagues (2023) compared leg extensions performed in the lengthened partial range versus the shortened partial range and found greater growth in parts of the quadriceps with lengthened partials. A systematic review and meta-analysis by Kassiano and colleagues comparing partial ranges found a small overall advantage favouring fuller ranges and lengthened partials over shortened partials. Meanwhile, work on passive stretch itself — including animal studies and a growing set of human trials using prolonged loaded stretching — suggests stretch under load is a genuine growth stimulus in its own right, though human effect sizes so far are modest and protocols (long daily stretching with devices) are not how anyone wants to spend their training time.
Mechanistically, the leading explanations involve higher passive tension at long lengths adding to active tension, and greater regional hypertrophy — several of these studies show growth concentrated in the distal portion of the muscle, which can change how a muscle looks even when total size changes are small. Worth noting: "long-length partials beat full range" is not what the data says overall. Full range of motion training performs at least as well in most comparisons; the cleaner finding is that the stretched portion of the range is the part you least want to skip, and shortened-position partials are the weakest option.
The practical application most coaches have landed on: choose exercise variations that load the stretch (deep stretch positions with control), don't cut the bottom of the range short to move more weight, and consider lengthened partials as a finisher technique rather than a replacement. Joint tolerance is the governor — a deep stretched position under load is also where some people's shoulders, elbows, or lower backs object, and no hypertrophy study is worth an injury.
Have you experimented with emphasising the stretched position — deep stretch variations, lengthened partial finishers, or loaded stretching — and did you notice anything beyond the extra soreness in week one?
The signal started with studies on exercises like overhead extensions versus pushdowns for the triceps, and preacher versus incline curls for the biceps, where the long-length condition grew more. Pedrosa and colleagues (2023) compared leg extensions performed in the lengthened partial range versus the shortened partial range and found greater growth in parts of the quadriceps with lengthened partials. A systematic review and meta-analysis by Kassiano and colleagues comparing partial ranges found a small overall advantage favouring fuller ranges and lengthened partials over shortened partials. Meanwhile, work on passive stretch itself — including animal studies and a growing set of human trials using prolonged loaded stretching — suggests stretch under load is a genuine growth stimulus in its own right, though human effect sizes so far are modest and protocols (long daily stretching with devices) are not how anyone wants to spend their training time.
Mechanistically, the leading explanations involve higher passive tension at long lengths adding to active tension, and greater regional hypertrophy — several of these studies show growth concentrated in the distal portion of the muscle, which can change how a muscle looks even when total size changes are small. Worth noting: "long-length partials beat full range" is not what the data says overall. Full range of motion training performs at least as well in most comparisons; the cleaner finding is that the stretched portion of the range is the part you least want to skip, and shortened-position partials are the weakest option.
The practical application most coaches have landed on: choose exercise variations that load the stretch (deep stretch positions with control), don't cut the bottom of the range short to move more weight, and consider lengthened partials as a finisher technique rather than a replacement. Joint tolerance is the governor — a deep stretched position under load is also where some people's shoulders, elbows, or lower backs object, and no hypertrophy study is worth an injury.
Have you experimented with emphasising the stretched position — deep stretch variations, lengthened partial finishers, or loaded stretching — and did you notice anything beyond the extra soreness in week one?