When people train with their muscles bunched up, the more their muscle fibers angle upward, the longer they can keep pushing hard before getting tired.

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Against

Evidence from Studies

Supporting (1)

46

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Differential changes in muscle architecture and neuromuscular fatigability induced by isometric resistance training at short and long muscle-tendon unit lengths.

Randomized Controlled Trial

Human

2020 Jul 1

The study found that when people trained with their muscles shortened, the way their muscle fibers angled (pennation angle) got bigger—and those with the biggest angle changes also got better at resisting muscle fatigue, just like the claim said.

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Source Study

Differential changes in muscle architecture and neuromuscular fatigability induced by isometric resistance training at short and long muscle-tendon unit lengths.

Score: 46

DOI: 10.1152/japplphysiol.00280.2020

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