Evaluation of joint motion based on perceived discomfort

Objective: To evaluate the discomfort degree of some joint motions. Method: Joints and joint motions were selected by referring to the national military standards. Twenty healthy male subjects participated in the experiment, discomforts for varying joint motions in standing and sitting postures were measured using the free modulus magnitude estimation. Relative discomfort index were educed to described overall change of discomfort degree of joint motions. Result: Perceived discomfort were affected by the joints, type of joint motions, and angle of motion. Results showed that the most comfort joint motions existed in the joint of shoulder and the most discomfort motion was in the hip in the experiment. Conclusion: The method and result in this study can provide reference and guidance for ergonomical evaluation by aviation design department, and drawing up of the military standards about postures comfort.