Elucidating The Mechanism Of Action Behind Instrument Assisted Soft Tissue Mobilization

Instrument Assisted Soft Tissue Mobilization (IASTM) is a clinical treatment using specialized tools to treat skin, fascia, muscles, and tendons. Studies suggest it enhances mobility and decreases pain. IASTM has also been referred to as a neuro-mobilization technique, it is thought to stimulate mechanosensitive neurons. Research on how IASTM affects the neuromuscular system is limited. PURPOSE: This study aims to test whether and how IASTM modulates lower extremity spinal excitability in healthy adults as measured by response in H-reflex amplitude. It is hypothesized that H-reflex amplitude will be reduced immediately after and stay altered for a short period of time after IASTM application. METHODS: 30 healthy adults volunteered to participate and signed informed consent approved by the IRB. Participants were randomly assigned to one of three equal groups (n = 10): control (C), sham (S), and instrument assisted soft tissue mobilization (IASTM). The IASTM group received 4-min treatment to the triceps surae. The S group received an intervention using the same strokes as IASTM, with a wooden tongue depressor and pressure less than 1 N. The C group received no intervention. Maximal motor response (Mmax) was recorded from the right soleus muscle by stimulating the tibial nerve to later elicit the proper H-reflex as percentage of Mmax. Ten baseline H-reflexes were recorded. Following intervention, this same procedure was performed immediately after and at, 1-, 5-, 10-, 15- and 30- minute intervals. Data was normalized to respective baselines. A 3 x 6 repeated measure ANOVA with factors of GROUP and TIME was used to evaluate the effects of the IASTM on H-reflex amplitude. Alpha was set at .05. RESULTS: Analysis revealed a significant main effect of TIME (F(5, 45) = 8.65, p = .0001), and significant interaction of GROUP x TIME (F(10, 90) = 3.49, p = .0006). Post-hoc analysis showed significant effects between C vs. IASTM and S vs. IASTM (p’s < 0.001) indicating that IASTM inhibits H-Reflex, 15 and 30- min post intervention. CONCLUSION: These results demonstrate an inhibitory effect of IASTM on H-reflex, 15 and 30-min post intervention. Thus, IASTM allows clinicians to decrease corticospinal excitability in healthy adults. Further research with larger sample sizes across diverse populations is warranted. This work was supported by The Rhode Island Foundation Medical Research Grant #14671_20231355, awarded to Mariusz Furmanek.