Does Stretching Make you Grow?
Unfortunately, the answer isn’t so simple. Excessive stretching of muscle fibres can lead to muscle injuries from a simple strain to a complete rupture – the opposite of growth. Once muscle injury has occurred healing progresses through phases:
Phase 1 = Destruction and is characterised by cell death and inflammation at the site of injury.
Phase 2 = Repair involves the regeneration of muscle fibres via satellite cells (undifferentiated cells) which proliferate and mature into myoblasts and ultimately muscle fibres - to replace the damaged fibres.
Phase 3 = Remodelling which occurs several months after injury with the formation of new blood vessels.
… therefore too much stretching can inhibit growth.
On the other hand, research in rat models have shown that stretching can promote growth of damaged muscles. The mechanical stretch stimulus can stimulate the activation of satellite cells and the differentiation of the activated satellite cells to accelerate the repair process (Phase 2) in the damaged muscle.
Ultimately, stretching exercises can prevent muscle injuries and enhance athletic performances but they can also cause injury so, a balance needs to be struck before any source of growth can occur!
Tanisha Burgher Fourth Year Medical Student, Cardiff University.
Milad Rouf Final Year Medical Student, Cardiff University.
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Fernandes, T. L. et al. 2011. MUSCLE INJURY – PHYSIOPATHOLOGY, DIAGNOSIS, TREATMENT AND CLINICAL PRESENTATION. Revista Brasileira de Ortopedia 46(3), pp. 247-255. doi: 10.1016/S2255-4971(15)30190-7
Mori, T. et al. 2017. Post-injury stretch promotes recovery in a rat model of muscle damage induced by lengthening contractions. The Journal of Physiological Sciences, doi: 10.1007/s12576-017-0553-9
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