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.

INTRODUCTION
SUBJECTS AND METHODS
    Subjects
    Outcomes Measure
    Interventions
    Data and Statistical Analysis
RESULTS
    Comparison of changes in the COP and muscleactivity and differences between the left- and rightsidemuscle activity in the experimental group
    Comparison of changes in the COP and muscle activityin the control group
    Comparison of changes in the COP and muscleactivity between the groups
DISCUSSION
CONCLUSION
ACKNOWLEDGMENT
REFERENCES

• Jeongil Kang(Department of Physical Therapy, Sehan University)
• Daekeun Jeong(Department of Physical Therapy, Sehan University)
• Hyunho Choi(Department of Physical Therapy, Sehan University) Corresponding author