The acute benefits and risks of passive stretching to the point of pain.

Abstract

This study evaluated the acute effects of two different stretch intensities on muscle damage and extensibility. Twenty-two physically active women (age 20±1.0years) were divided into two matched groups and undertook eight sets of 30-s passive hamstring stretching. One group stretched to the point of discomfort (POD) and the other to the point of pain (POP). Hamstring passive torque, sit and reach (S&R), straight leg raise (SLR), and markers of muscle damage were measured before, immediately after stretching and 24h later. S&R acutely increased and was still increased at 24h with median (interquartile range) of 2.0cm (0.5-3.75cm) and 2.0cm (0.25-3.0cm) for POP and POD (p<0.05), respectively, with no difference between groups; similar changes were seen with SLR. Passive stiffness fully recovered by 24h and there was no torque deficit. A small, but significant increase in muscle tenderness occurred at 24h in both groups and there was a very small increase in thigh circumference in both groups which persisted at 24h in POP. Plasma CK activity was not raised at 24h. Stretching to the point of pain had no acute advantages over stretching to the discomfort point. Both forms of stretching resulted in very mild muscle tenderness but with no evidence of muscle damage. The increased ROM was not associated with changes in passive stiffness of the muscle but most likely resulted from increased tolerance of the discomfort.