Stretching is an integral part of physical therapy treatment at In Motion Physical Therapy. It increases muscle length, promotes alignment of muscle fibers, and improves joint range of motion (ROM). Stretching also decreases pain associated with musculoskeletal conditions like arthritis or overuse. Because of this, stretching is an important part of a comprehensive exercise program for overall health.

Benefits of Stretching

Stretching is a beneficial part of any exercise routine, but the best type of stretching is controversial.  Results depend on the individual. Gender, pain, orthopedic issues, ability to move, and compliance all play a role. What works for some patients may not work for others, even if they are being treated for something similar.

Recent research on stretching focuses on the difference between passive versus active stretching. Researchers choose the hamstring muscles to study because their length is easy to measure, and many people in the general population have tight hamstrings.

Types of Stretching

Passive stretching is defined as a form of stretching where an outside force is applied to a limb This force may be a partner assist, a strap, gravity, or one’s body weight. On the other hand, active stretching involves purposefully contracting the muscle you are trying to stretch.

The Meroni Study

Meroni et al. (2010) compared active stretching to passive stretching of the hamstrings. The study assessed hamstring flexibility following 3 and 6 weeks of stretching. The group who performed active stretching of the hamstrings had a significant increase in ROM compared to the passive stretching group.

A portion of the initial group was reevaluated 4 weeks following the conclusion of the study. Results demonstrated the active stretching group maintained a 6 degree ROM improvement, while the passive stretching group didn’t maintain any significant change.

The Fasen Study

Fasen et al. (2010) compared active stretching of the hamstring versus passive stretching in another high quality study. Four different techniques were used: two active hamstring stretches and two passive hamstring stretches.

The study assessed the participants’ hamstring flexibility at 4 and 8 weeks following initiation of stretching. Study results determined both active and passive stretching is effective in increasing hamstring flexibility. At the 4 week mark, 3 of the groups (two performing active hamstring stretches, one performing passive stretches) showed improvement in hamstring flexibility. However, the two active stretching groups showed the greatest improvement.

Interestingly enough, at the 8 week mark, one of the groups performing passive hamstring stretching showed the most improvement in hamstring flexibility.

So which is best?

Based on these studies, 6-8 weeks of active or passive stretching is effective in improving hamstring flexibility. Clinically, stretching is often prescribed twice daily over a 6-8 week period for maximum gains. The amount of time you need to spend stretching depends on your goals and your therapist.

The American College of Sports Medicine (ACSM) recommends individuals perform passive or active stretching, following a light aerobic warm-up at least 2 to 3 days per week. It is recommended that each stretch be held for 15-30 seconds and repeated 2 to 4 times.


In conclusion, stretching is an important component of both physical therapy treatment and a comprehensive exercise program. Both active and passive stretching are effective in increasing muscle flexibility. Depending on the patient and clinician preference, some stretches may be more effective than others. Please seek guidance from a physical therapist or other medical professional prior to initiating a stretching routine to decrease injury risk.


  1. Page, P. (2012). Current Concepts in Muscle Stretching for Exercise and Rehabilitation International of Journal Sports Physical Therapy, 7(1), 109–119.
  2. Fasen, J.M., O’Connor, A.M., Schwartz, S.L., et al.(2010). A Randomized Controlled Trial of Hamstring Stretching: Comparison of Four Techniques. Journal of Strength and Conditioning, 23(2), 660-667.
  3. Meroni, R., Cerri, C.G., Lanzarini, C., et al. (2010). Comparison of Active Stretching Technique and Static Stretching Technique on Hamstring Flexibility. Clinical Journal of Sports Medicine, 20(1), 8-14.