Pelvic restraint effect on lumbar gluteal and hamstring muscle electromyographic activation

Objective: To evaluate the influence of pelvic restraint on electromyograph ic activation (neural drive) of the lumbar extensor, gluteal, and hamstring muscles during submaximal dynamic lumbar extension in an upright seated po sition. Design: Randomized, balanced, crossover trial comparing the electromyograph ic activation of the lumbar, gluteal, and hamstring muscles during dynamic lumbar extension exercise with and without pelvic restraint. Setting: Research laboratory at a private research university. Subjects: Twelve apparently healthy men (ages 18 to 50yrs). Intervention: Dynamic lumbar extension exercises. Main Outcome Measure: Electromyographic recordings. Results: Pelvic restraint did not influence the relative activation of the lumbar, gluteal, or hamstring muscle groups (p less than or equal to.05) du ring submaximal dynamic lumbar extension exercise. The relative activation of the gluteal muscles was significantly lower than that of the lumbar exte nsor and hamstring muscle groups. Conclusions: Pelvic restraint is not a requirement to promote neural drive to the lumbar musculature during submaximal dynamic lumbar extension exerci se performed in an upright seated position. Submaximal lumbar extension exe rcise reduces the relative contribution of the gluteal muscles compared wit h a maximal voluntary isometric contraction. (C) 1999 by the American Congress of Rehabilitation Medicine and the Americ an Academy of Physical Medicine and Rehabilitation.