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Clinical study: IASTM therapy in combination with stretching shows better results than twisting stretching.

Clinical study: IASTM therapy in combination with stretching shows better results than twisting stretching.

These findings support the effectiveness of Proprioceptive Neuromuscular Facilitation (PNF) and Instrumental Soft Tissue Mobilization (IASTM) compared to static stretching for improving hip flexibility. Proven effective for a shorter period of time than an equivalent static stretching program. Level of evidence: 1b.


Tight thigh muscles can cause ineffective movements and increase the risk of injury. Static stretching is commonly used for this, but doctors are also exploring alternatives called Instrumental Soft Tissue Mobilization (IASTM) and Proprioceptive Muscle Facilitation (PNF). In this study, we review two studies with the same goal: to show that IASTM or PNF may be superior to static stretching for improving hip flexibility.

Research methods

The study involved adults without disabilities who were recruited on a university campus. IASTM Study: N = 17 (11 men and 6 women). PNF study: N = 23 (7 men and 16 women). Hip range of motion was measured using passive straight leg raise (for IASTM) or active straight leg raise (for PNF) before and after stretching. Participants performed independent static stretching on one leg and received alternating exposure on the opposite leg. The two studies were analyzed separately for reliability measures and significant differences between interventions.


Measurements of hip flexibility showed high reliability in both studies (intraclass correlation coefficient = 0,97) with a minimal quantifiable change of less than 4,26. Both studies showed significant interactions between time and intervention (p < 0,05). Additional analysis showed that PNF and IASTM interventions resulted in greater increases in hip range of motion than static stretching. These results demonstrate the effectiveness of PNF and IASTM techniques compared to static stretching for improving hip flexibility. These interventions provide more effective alternatives for improving flexibility in the clinic, allowing greater results to be achieved in a shorter period of time than an equivalent static stretching program.

PNF (Proprioceptive Muscle Facilitation)

PNF is a method based on the physiological mechanism of the reflex, which is responsible for the activation of the special Golgi-Tendon organ and causes autogenous inhibition in the agonist muscle. This method includes a sequence of static and active phases of muscle stretching and contraction.


To achieve the goal of the study, two separate experiments were conducted using the IASTM and PNF methods, compared to static stretching. The IASTM experiment involved 17 adults, while the PNF experiment selected 23 participants. Hip flexibility was determined using passive straight leg raise for IASTM and active straight leg raise for PNF before and after stretching. Each participant underwent static stretching on one leg and an alternative method (IASTM or PNF) on the other leg. The results of both studies showed high reliability (intraclass correlation coefficient = 0,97) and accuracy of measurements, with a Minimum Variable Threshold of less than 4,26 degrees (detailed data are shown in Table 2).

The results of these studies indicate that both IASTM and PNF resulted in significant improvements in hamstring flexibility compared to static stretching. These findings support previous studies showing greater efficacy of PNF compared to static stretching and indicate that IASTM may be an effective method for improving hip flexibility. Although these studies did not directly compare PNF and IASTM, they suggest that both techniques can be used to achieve better results than an equivalent static stretching program.


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