Mechanical deformation of posterior thoracolumbar fascia after myofascial release in healthy men: A study of dynamic ultrasound imaging

Myofascial release (MR) on the posterior thoracolumbar fascia (PLF) is one of the manual techniques aim to restore the normal length and tension of restricted fasciae and muscles. The present study aimed to quantify the immediate effects of MR on fascial properties of the PLF in healthy men. Cross-sectional study. Participants (N = 10, aged 22.8 ± 2.0 years) performed a press-down to maximal voluntary contraction (MVC) in the prone position. Deformation of the PLF was measured using an ultrasonographic apparatus. Force output was simultaneously measured. The stiffness index and hysteresis index were then represented by the slope of the loading curve, and the percentage of the area within the loading–unloading curve. One-way ANCOVA was used to compare differences in the stiffness index or hysteresis index of the PLF before and after MR. Two-way repeated ANOVA was used to compare deformation of the PLF or force output after MR. The primary findings included a decrease (before: 24.1 ± 8.3 vs. after: 18.9 ± 5.3 N/mm; mean difference, −5.2 ± 4.9 N/mm, p = 0.002