ABSTRACT

Objective : This study intended to provide research materials for the proper positioning of the keyboard for computer work by individuals with a thoracic SCI based on the experimental data on the EMG activity of eight muscles related to computer work. Methods : The subjects used were 9 and 11 patients with a complete high (T2-T8) or low (T9-T12) thoracic SCI (T2-T8) of A or B as categorized by the American Spinal Injury Association (ASIA), respectively, along with 9 able-bodied individuals. All participants were given the task of typing on the middle line of the keyboard at a speed of 4 characters per second at a rhythm from a metronome for 2 minutes at 2 keyboard heights (elbow flexion of more than 100°, elbow flexion of 70°) During the experiment, the EMG activity (%RVC) of the muscles of the neck and shoulder, such as the cervical erector spinae, upper trapezius, anterior deltoid, posterior deltoid, and middle trapezius, the wrist extension muscle group and the minor muscles maintaining the body core of the individuals with an SCI, such as the latissimus dorsi and pectoralis major, were measured using a surface EMG. Results : The EMG activity of the patients with high and low thoracic SCI was low for the keyboard positioning at an elbow flexion of 70°, which is similar for the anterior deltoid, latissimus dorsi, and wrist extensor muscle group of the able-bodied individuals. Also, for the low thoracic SCI patients, the positions where the elbow flexion angle increased to more than 100°showed high EMG activities of the cervical erector spinae and latissimus dorsi, which was different from the other groups. Conclusion : It was identified that an elbow flexion of 70°is an appropriate work posture for individuals with an SCI. It is thought that further study with a longer research time span and more test subjects should be conducted to explore an appropriate VDT environment for individuals with an SCI under comprehensive computer work conditions.