A 2015 study was done to answer the question of how much stretch and for how long is optimal to reduce pain, increase range of motion and improve physiologic function of joints. Myofascial release (MFR) is a physical therapy using long-held, static stretches. It was employed to stress joints and was shown to reduce inflammation and improve healing response to injury.
The researchers found that a strain (elongation) of 3% held for 5 minutes is ideal. Stresses above that level, which created a strain of 9% or 12% (that is a lot!), can cause problems, but a stress resulting in only a 3% strain can accelerate healing. The longer the stress is applied the better. The lengths of time varied from 1 to 5 minutes. This, in our Yin Yoga context, means less effort and longer holds are better. The researchers concluded, “Longer duration of MFR resulted in rapid decreases in wound size.”
Thanh V. Cao et al., “Duration and Magnitude of Myofascial Release in 3- Dimensional Bioengineered Tendons: Effects on Wound Healing,” The Journal of the American Osteopathic Association 115.2 (2015): 72–82.