The effect of the diaphragm stretching technique in the diaphragm contraction rate and trunk muscle activity in back pain patients

BACKGROUND: The diaphragm plays an important role in trunk stability. Therefore, diaphragmatic dysfunction is associated with low back pain. OBSECTIVE: This study aimed to confirm the effectiveness of diaphragm stretching technique as a treatment method for low back pain by evaluating the diaphragm contraction rate, trunk muscle activity in patients with low back pain. METHODS: Thirty-four patients with low back pain were randomly divided into two group: an experimental group and a control group. The diaphragm stretching technique was conducted in the experimental group and the placebo intervention was conducted in the control group. The diaphragm stretching technique was conducted once, maintaining the tension for 7 min. The placebo intervention was conducted in the same position as the diaphragm stretching technique but with only light contact maintained without pressure. The diaphragm contraction rate and trunk muscle activity were measured before and after the intervention, and the changes were compared and analyzed. A paired sample t-test was used to compare measurements before and after the intervention within the group. An independent t-test was used to compare the experimental and control group. Statistical significance (α) was set at 0.05. RESULTS: In the experimental group, the diaphragm contraction rate increased significantly after the intervention. Trunk muscle activity decreased significantly (p< 0.05). However, all domains in the control group receiving the placebo intervention were not significantly different (p> 0.05). Comparative analysis of changes before and after the intervention between the groups showed significant differences in the diaphragm contraction rate and trunk muscle activity in the experimental group (p< 0.05). CONCLUSION: The diaphragm stretching technique improved the diaphragm contraction rate and trunk muscle activity was lower due to the improved trunk stabilization function of the diaphragm. Therefore, the diaphragm stretching technique can be recommended as a physical therapy intervention to improve pain in patients with low back pain.