Immediate Effect of Lumbar Mobilization on Paraspinal Muscle Stiffness

Overview

This randomized controlled crossover study will investigate the immediate effect of central posteroanterior lumbar mobilization on the intrinsic stiffness of the erector spinae and multifidus muscles in healthy adults without low back pain. Twenty-four participants will complete two experimental visits in randomized order. During one visit, participants will receive Maitland Grade III++ central posteroanterior mobilization at the L4 vertebral level, while during the other visit they will receive a sham mobilization condition involving gentle rhythmic pressure. Muscle stiffness will be assessed using shear wave elastography immediately before and after each intervention.

The study will be designed as a randomized controlled crossover trial to investigate the immediate effects of manual spinal mobilization on lumbar paraspinal muscle stiffness in healthy adults without low back pain. Each participant will attend two separate study visits and will receive both experimental conditions in a randomized order. In the experimental condition, Maitland Grade III++ central posteroanterior mobilization will be applied over the spinous process of L4. The intervention will consist of three 60-second sets of passive rhythmic oscillatory pressures performed at approximately 2 Hz, with 30-second rest periods between sets. In the control condition, participants will receive a sham mobilization presented as a Grade I mobilization technique. The sham intervention will follow the same timing structure but will consist of gentle rhythmic pressure over the L4 spinous process. Intrinsic muscle stiffness of the right erector spinae and multifidus muscles will be assessed using shear wave elastography. Three measurements will be obtained immediately before and after each intervention, and the mean value will be expressed in kilopascals. Measurements will be performed in a standardized prone position at the L4-L5 level.