Original articleEffects of external pelvic compression on trunk and hip muscle EMG activity during prone hip extension in females with chronic low back pain

Many studies have reported higher trunk and hip muscle activity in patients with chronic low back pain (CLBP). Increased trunk and hip muscle activity could contribute to pain. Previous studies have shown that external pelvic compression (EPC) decreased back and hip muscle activity during physical tasks.In this study, we assessed the effects of EPC on the electromyography (EMG) activity of the latissimus dorsi (LD), elector spinae (ES), gluteus maximus (GM), and biceps femoris (BF) in a CLBP group and a healthy group during prone hip extension (PHE).Forty female volunteers (20 non-specific CLBP, 20 healthy) were recruited. Surface EMG data were collected from the LD, ES, GM, and BF muscles during a PHE task. Normalized EMG values were analyzed by separate repeated-measures analysis of variance (ANOVA) for each muscle.The normalized EMG activity in the left LD, bilateral ES, and right GM was significantly higher in the CLBP group than in the healthy group during PHE. In the CLBP group, the normalized EMG activity in the left LD, bilateral ES, and right GM was significantly lower with EPC than without (p < 0.05). This suggests that the application of EPC decreased trunk and hip extensor EMG activity in the CLBP group during PHE.