Asymmetrical trunk muscle activities and kinematics during dominant and nondominant leg lifts in subjects with lumbar rotation with flexion syndrome

Abstract

BACKGROUND: Patients with lower back pain due to lumbar rotation with flexion syndrome (LRFS) have greater asymmetry of rotation in the lumbopelvic region than healthy people. OBJECTIVE: To understand the activities of the trunk muscle and kinematics of the trunk and pelvis in patients with LRFS during the bird-dog (BD) exercise with dominant non-dominant leg lifts, a frequently prescribed stabilization exercise. METHODS: We compared activity and kinematics during the BD exercise with dominant and non-dominant leg lifts in 11 patients (6 male, 5 female) with LRFS who were recruited from a university. RESULTS: Significantly lower activation of the ipsilateral erector spinae muscle was found during the nondominant leg lift than the dominant leg lift in patients performing the BD exercise (t = −3.71, p = 0.04). In addition, the trunk was significantly flexed during the dominant leg lift (t = −6.069, p = 0.00) and bent to the right side (t = 3.131, p = 0.01) during both dominant and nondominant leg lifts. CONCLUSIONS: These results imply the presence of asymmetrical muscle activity and kinematics in the trunks of subjects with LRFS. This information should be considered for prescribing exercises to such subjects.