The aim of this study was to investigate the effect of myofascial release technique on rib cage mobility, respiratory function, respiratory muscle strength and endurance in patients with hamstring muscle shortness.

Hamstring flexibility is important to maintain activities such as walking and running in daily life. Hamstring muscle shortness, commonly seen in the community, is a risk factor for many musculoskeletal pathologies. Clinical observations have shown that the shortness of the Hamstring muscle causes spinal malalignment. This deterioration of the spine alignment may adversely affect the rib cage expansion. Moreover, considering that the optimal length of the muscles provides optimal contraction, it was found that the spinal malalignment adversely affected the effective contraction of the diaphragm by changing the position of diaphragm. A different view is that, because the fascia functions as a single tissue surrounding the entire body, a restriction in the hamstring muscle can also cause a restriction in distal muscles such as diaphragm through the fascia.

There are many treatment methods used to increase the flexibility of the hamstring muscle. One of these methods is the myofascial release technique. In this technique, which targets both muscle and fascia, applying light and prolonged pressure provides the myo-fascial complex to reach its optimal length, resulting in the optimal function of the muscle. In our best knowledge, no study has evaluated the effect of myofascial release technique on respiratory parameters in patients with hamstring muscle shortness.

Inclusion Criteria:

• more than 15 degrees knee flexion angle during popliteal angle test,
• no generalized joint laxity according to Beighton Criteria, and
• no musculoskeletal problems of lower extremities.

Exclusion Criteria:

• history of lower extremity and/or axial skeletal fracture;
• recent muscle, tendon injury in lower extremity;
• history of lumbal disc herniation, arthritic and/or inflammatory disease;
• obesity, diabetes and/or metabolic syndrome;
• history of surgery in the last month,
• using muscle relaxant medication in the last month;
• received manual therapy in the last month