4. Discussion
MUSCLE RELAXATION
Essential to our knowledge, this is the first study to use ultrasound imaging to measure fascial structures as an indicator of the outcome of a percussion massage treatment intervention. The current study found that a 15 min PT did not change TLF thickness and lumbar flexibility. However, it increased the skin temperature of participants, as well as decreased the TLF echointensity and perceived stiffness.The working mechanism of PT combines elements of percussive massage and vibration. On the one hand, PT can induce tonic vibration reflexes by vibrating at specific frequencies to reduce stress on muscles and connective tissues [Echo intensity is a first-order statistical quantitative ultrasound descriptor commonly used to assess tissue texture characteristics and quality by tissue echo [The results of ANCOVA demonstrated significantly lower perceived stiffness in the PT group after the intervention compared to the control group. A consideration is the stimulation of Ruffini cylinders and Pacinian vesicles in the fascia during PT, which may lead to inhibition of sympathetic activation and muscle relaxation [