CONTEXT: Individuals with a history of low back pain (LBP) may present with decreased hip-abduction strength and increased trunk or gluteus maximus (GMax) fatigability. However, the effect of hip-abduction exercise on hip-muscle function has not been previously reported. OBJECTIVE: To compare hip-abduction torque and muscle activation of the hip, thigh, and trunk between individuals with and without a history of LBP during repeated bouts of side-lying hip-abduction exercise. DESIGN: Repeated measures. SETTING: Clinical laboratory. PARTICIPANTS: 12 individuals with a history of LBP and 12 controls. INTERVENTION: Repeated 30-s hip-abduction contractions. MAIN OUTCOME MEASURES: Hip-abduction torque, normalized root-mean-squared (RMS) muscle activation, percent RMS muscle activation, and forward general linear regression. RESULTS: Hip-abduction torque reduced in all participants as a result of exercise (1.57 ± 0.36 Nm/kg, 1.12 ± 0.36 Nm/kg; P < .001), but there were no group differences (F = 0.129, P = .723) or group-by-time interactions (F = 1.098, P = .358). All participants had increased GMax activation during the first bout of exercise (0.96 ± 1.00, 1.18 ± 1.03; P = .038). Individuals with a history of LBP had significantly greater GMax activation at multiple points during repeated exercise (P < .05) and a significantly lower percent of muscle activation for the GMax (P = .050) at the start of the third bout of exercise and for the biceps femoris (P = .039) at the end of exercise. The gluteal muscles best predicted hip-abduction torque in controls, while no consistent muscles were identified for individuals with a history of LBP. CONCLUSIONS: Hip-abduction torque decreased in all individuals after hip-abduction exercise, although individuals with a history of LBP had increased GMax activation during exercise. Gluteal muscle activity explained hip-abduction torque in healthy individuals but not in those with a history of LBP. Alterations in hip-muscle function may exist in individuals with a history of LBP.
CONTEXT: Individuals with a history of low back pain (LBP) may present with decreased hip-abduction strength and increased trunk or gluteus maximus (GMax) fatigability. However, the effect of hip-abduction exercise on hip-muscle function has not been previously reported. OBJECTIVE: To compare hip-abduction torque and muscle activation of the hip, thigh, and trunk between individuals with and without a history of LBP during repeated bouts of side-lying hip-abduction exercise. DESIGN: Repeated measures. SETTING: Clinical laboratory. PARTICIPANTS: 12 individuals with a history of LBP and 12 controls. INTERVENTION: Repeated 30-s hip-abduction contractions. MAIN OUTCOME MEASURES: Hip-abduction torque, normalized root-mean-squared (RMS) muscle activation, percent RMS muscle activation, and forward general linear regression. RESULTS: Hip-abduction torque reduced in all participants as a result of exercise (1.57 ± 0.36 Nm/kg, 1.12 ± 0.36 Nm/kg; P < .001), but there were no group differences (F = 0.129, P = .723) or group-by-time interactions (F = 1.098, P = .358). All participants had increased GMax activation during the first bout of exercise (0.96 ± 1.00, 1.18 ± 1.03; P = .038). Individuals with a history of LBP had significantly greater GMax activation at multiple points during repeated exercise (P < .05) and a significantly lower percent of muscle activation for the GMax (P = .050) at the start of the third bout of exercise and for the biceps femoris (P = .039) at the end of exercise. The gluteal muscles best predicted hip-abduction torque in controls, while no consistent muscles were identified for individuals with a history of LBP. CONCLUSIONS: Hip-abduction torque decreased in all individuals after hip-abduction exercise, although individuals with a history of LBP had increased GMax activation during exercise. Gluteal muscle activity explained hip-abduction torque in healthy individuals but not in those with a history of LBP. Alterations in hip-muscle function may exist in individuals with a history of LBP.
Authors: Sean Sadler; Samuel Cassidy; Benjamin Peterson; Martin Spink; Vivienne Chuter Journal: BMC Musculoskelet Disord Date: 2019-10-22 Impact factor: 2.362