Three-dimensional kinematics and trunk muscle myoelectric activity in the young lumbar spine: A database

Objective: To document the three-dimensional (3D) kinematics of the lumbar spine and the myoelectric activity of trunk muscles throughout the range of motion in selected tasks performed by healthy subjects. Design: A survey of a single population. Setting: A research laboratory in a university setting. Participants: Twenty-four men and women, university-age, with no history of chronic lower back pain volunteered for this study. Interventions: The selected tasks consisted of lateral bend and axial twists to the right and left plus four different flexion-extension tasks that varied a hand-held weight (10kg and 0kg), and flexion-extension velocity (free-paced and 20°/ sec). Main Outcome Measure: 3D lumbar spine kinematics and normalized, linear enveloped electromyogram (EMG) of trunk muscles. Results: The motion time histories were illustrated graphically. Consistent spinal kinematics and EMG activation patterns during each task across subjects were seen. Peak displacement values between tasks, using one-way analysis of variance, showed no significant difference. Conclusion: A database of healthy spine kinematics and normalized linear enveloped trunk muscle activation patterns were developed for future comparison of elderly and pathological subjects.