Effect of various wheelchair handle grip directions on muscle activities of upper body of assistant during movement on ascending and descending ramps

[Purpose] This study aims to determine the effects of various wheelchair handle grip directions on the muscle activities of the upper body of an assistant during movement on ascending and descending ramps. [Subjects and Methods] The study subjects were 17 young and healthy participants whose mean age, height, and weight was 23.0 ± 2.7 years, 175.5 ± 4.7 cm, and 70.0 ± 14.2 kg, respectively; all subjects voluntarily consented to participate. Three grip directions were tested: general grip, medial grip, and neutral grip. Muscle activities in the serratus anterior, rhomboid, erector spine, biceps brachii, triceps brachii, bracioradialis, flexor carpi radialis, and extensor carpi radialis were measured using an electromyograph (EMG). [Results] Significant differences were seen in the muscle activities of the biceps brachii, bracioradialis, and flexor carpi radialis during wheelchair movement on an ascending ramp and in the biceps brachii and triceps brachii during movement on a descending ramp. [Conclusion] Measurement results showed that the general grip resulted in the highest muscle activities in the upper body of assistants during wheelchair movement on both ascending and descending ramps.