Background: Patients with low back pain (LBP) experience misalignments in the center of pressure (COP) and muscle imbalances due to frequent onesided posture adjustments to avoid pain. Objectives: To identify the effects of Squat Exercises with Vertical Whole-Body Vibration on the Center of Pressure and Trunk Muscle Activity. Design: Randomized controlled trial. Methods: Thirty LBP patients with an imbalance in the COP were sampled and randomly assigned to an experimental group of 15 patients who under went an intervention involving squat exercises with vertical WBV and a control group of 15 patients who were treated via a walking intervention. As pretests before the interventions, the subjects’ COP was identified by measuring their stability index (ST), and erector spinae, rectus abdominis, transverse abdominis, gluteus medius muscle activity was analyzed by determining the % reference voluntary contraction (%RVC) value using surface electromyography while sit to stand. After four weeks, a post test was conducted to remeasure the same variables using the same methods. Results: Statistically significant differences were found in the ST (P<.01) and trunk muscle (P<.05, P<.001) in the experimental group before and after the intervention. In terms of the differences between the left- and right-side (RL) muscle activity, only the transverse abdominis (TrA) and gluteus medius (GM) exhibited statistically significant increase (P<.05). A comparison of the groups showed statistically significant differences in the TrA with respect to muscle activity (P<.05) and in the RLTrA and RLGM in terms ofthe difference between left- and right-side muscle activity (P<.01). Conclusion: Squat exercises with vertical WBV produced effective changes in the COP of patients with LBP by reducing muscle imbalances through the delivery of a uniform force. In particular, strengthening the TrA and reducing an imbalance in the GM were determined to be important factors in improving the COP.

Background: Lumbar disc herniation (LDH) causes neurological symptoms by compression of the dura mater and nerve roots. Due to the changed in proprioception inputs that can result in abnormal postural pattern, delayed reaction time, and changed in deep tendon reflex. Objective: To investigate the effects of lumbar stabilization exercises on motor neuron excitability and neurological symptoms in patients with LDH. Design: Randomized Controlled Trial (single blind) Methods: Thirty patients with LDH were recruited; they were randomly divided into the balance center stabilization resistance exercise group (n=15) and the Nordic walking group (n=15). Each group underwent their corresponding 20- minute intervention once a day, four times a week, for four weeks. Participants’ motor neuron excitability and low back pain were assessed before and after the four-week intervention. Results: There were significant differences in all variables within each group (p<.05). There were significant differences between the experimental and control groups in the changes of upper motor neuron excitability and pain (p<.05), but not in the changes of lower motor neuron excitability and Korean Oswestry Disability Index. Conclusion: Lumbar stabilization exercises utilizing concurrent contraction of deep and superficial muscles improved low back function in patients with LDH by lowering upper motor neuron excitability than compared to exercises actively moving the limbs. Lumbar stabilization exercises without pain have a positive impact on improving motor neuron excitability.