04/22/2026
Stretching theories have been leaning away from a highly mechanical perspective to a combination of neural, psychosocial, behavioral, and structural/mechanical factors in the past 30-plus years.
In 2010, Weppler and Magnusson reported in Physical Therapy four primary mechanical theories on muscle extensibility: Viscoelastic deformation, plastic deformation of connective tissues, increased number of sarcomeres, and neuromuscular relaxation.
Some researchers in the 1990s tested these mechanical theories and found that stretching increases stretch tolerance with little physical change to muscle extensibility and its structure. Weppler and Magnusson called this the “sensory theory” where changes to muscle extensibility are primarily caused by the nervous system.
They also attributed a person's subjective sensation to the elongated muscle feeling.
Details: https://massagefitnessmag.com/fitness/why-stretching-theories-lean-toward-neural-explanations-less-mechanical/
