Effect of the technique taught in acupuncture practice on muscle hardness: Comparison in fascia and muscle

[Purpose] In acupuncturist or moxibustionist training schools, we teach students the sparrow pecking technique, a basic acupuncture technique, to stimulate muscles and fascia and observe the changes in muscle hardness.[Method] Eight faculty members and students from the Morinomiya University of Medical Sciences, who consented to the study content and had no issues at the stimulation site, were included in the study. After instructing the participant to rest in the supine position, the left and right tibialis anterior muscles were stimulated with either fascial stimulation (Fascia: Group F) or intramuscular stimulation (Muscle: Group M). The intervention order was randomized according to random numbers created by a computer. The insertion site in the tibialis anterior muscle was the site of muscle tension found via palpation. The acupuncture needle used for the procedure was a 0.20 × 50 mm disposable acupuncture needle manufactured by Seirin Corporation, and the muscle or fascia was needled while positioning the acupuncture tip using ultrasonic diagnostic equipment. After reaching the target depth, the sparrow pecking technique was performed 10 times, moving the needle up and down within a range of 5 mm, once per second. The muscle hardness was measured with shear wave elastography (SWE) using ultrasonic diagnostic equipment (Aplio500, Canon Medical Systems Corporation). Measurements were recorded eight times in total: before acupuncture, after skin penetration, after stimulation with the sparrow pecking technique, 5 minutes after retaining the needle, 10 minutes after retaining the needle, immediately after removing the needle, 5 minutes after removing the needle, and 10 minutes after removing the needle.[Results] Neither group showed any significant change in SWE when compared to the pre-acupuncture values. Group F showed a decreasing trend in SWE during needle retention, while Group M showed an increasing trend. The results of calculating the amount of change from the pre-insertion value in both groups and comparing the values of the groups showed that the value was significantly lower in Group F 10 minutes after retaining the needle (p < 0.01), and this tendency persisted for up to 10 minutes after removal of the needle (p < 0.05).[Discussion] There was no decrease in the SWE values with the sparrow pecking technique, a basic acupuncture technique used to train students. However, Group F and Group M exhibited different changes over time. There was a significant difference between the groups, suggesting that Group F may have had a greater reduction in muscle hardness. In acupuncture training schools, students are often instructed to ascertain the change in the hardness of deep tissue from the sensation of resistance felt via the acupuncture needle when it is inserted. However, there was no clear change in SWE with the technique used in this study. The differences could be due to variations in the stimulated tissue. The above results suggest the necessity of reconsidering the technique guidance taught to students.