Abstract
Objective: To investigate the kinematics, functional sub-tasks, and excitation levels of the trunk and upper extremity muscles of paraplegic subjects during walker-assisted locomotion. Design: Retrospective cross-sectional study. Setting: Gait analysis laboratory. Participants: Eight individuals with spinal cord injury at T12, lower extremity motor score less than 4, and capable of walking independently with the assistance of ankle-foot orthosis and walker. Main Outcome Measures: Kinematics of pelvis, trunk, shoulder and elbow; trajectory of center of mass; and electromyography (EMG) activity of trunk and upper extremity muscles during gait. Results: Four subtasks were characterized for each locomotion step, based on the kinetics and kinematics data: (1) balance adjustment, (2) walker propulsion, (3) leg raising, and (4) leg swing. The latter two involved large lateral maneuvres by the trunk and pelvis and appeared to be the most skill- and muscle activity-demanding subtasks. The main muscles contributing into these subtasks were the ipsilateral paraspinal and abdominal muscles, as well as the contralateral scapulothoracic and shoulder girdle muscles, with EMG intensities significantly higher than their minimum mean intensities (P < 0.05) and those of the contralateral side (P < 0.05). Conclusions: Our results provide more insight into the functional sub-tasks and muscular demands of walker-assisted paraplegic gait that can help to design appropriate muscle strengthening programs, as well as developing more effective gait orthoses.