Asymmetric myoelectric activity pattern of spinal and hip muscles during sit-to-stand and gait tasks in adolescents with idiopathic scoliosis

Objective: The study aimed to investigate the recruitment patterns of the lumbar longissimus (Long), iliocostalis (Ilio), and gluteus medius (Gme) muscles from both sides (Cv and Cx) of the lumbar spine of adolescents with IS, during the sit-to-stand and gait movements, and to correlate their myoelectric activation with the magnitude of scoliosis.Methods: The sEMG signals from these muscles were recorded in fifteen right-handed adolescents (4 males; age: 14.7 ± 1.9 years). A footswitch synchronized sEMG recordings during 1-minute motor tasks. The root-mean-square value was extracted from the sEMG signals. Results: Significant differences were found between Cv and Cx sides in Long sEMG activity during standing (P=0.026) and sitting (P=0.015). Besides, there was a significant difference in Long recruitment at the beginning of the support phase of gait (P=0.007). Ilio activity on the Cx side correlated with the Cobb angle during standing (P=0.003; r=0.71) and sitting (P=0.03; r=0.55). Conclusion: Long exhibited an asymmetric recruitment, more pronounced in the convexity during sit-to-stand tasks and early stance phase. Ilio activity correlated positively with the Cobb angle during sit-to-stand and gait, potentially indicating scoliotic curve progression.