Effect of wearable chair on gait, balance, and discomfort of new users during level walking with anterior loads

• Published in: Journal of safety research Vol. 87; pp. 27 - 37
• Main Authors: Li, Ying-yi, Gan, Jing
• Format: Journal Article
• Language: English
• Published: United States 01.12.2023
• Subjects: Exoskeleton Device - adverse effects; Gait - physiology; Healthy Volunteers; Humans; Movement - physiology; Pain - etiology; Pain - physiopathology; Postural Balance - physiology; Walking - physiology; Wearable Electronic Devices; Wearable Chair; Discomfort; Ergonomics; Gait Balance; Occupational Health
• ISSN: 0022-4375; 1879-1247; 1879-1247
• DOI: 10.1016/j.jsr.2023.08.013

Walking with anterior loads is common in industrial scenarios, but as exoskeletons are increasingly used in work environments to alleviate musculoskeletal disorders (MSDs), this new "human-robot" system composed of the human body and exoskeleton may be associated with new risks and harm that warrant further investigation. Therefore, this study will discuss the effect of a wearable chair on the gait, balance, and discomfort of new users with different weights of anterior loads during level walking. Twenty-two healthy subjects (sex balanced) participated in the experiment. Each exposure comprised one of two exoskeleton states (with/without) and four load conditions: No carried load, carrying an empty box (0.3 kg), 5%Body Weight (BW), and 10%BW. The order of exoskeleton states and load conditions was randomly assigned. Using an eight-camera motion capture system to record the entire movement. And the subjective discomfort and perceived balance after each exposure were recorded on an 11-point numeric rating scale, respectively. Using SPSS 26.0 software (IBM Inc., Chicago) to conduct statistical analyses. Level walking with a wearable chair in different load conditions significantly affected gait parameters (like cadence) and gait balance. The perceived balance decreased with the exoskeleton, consistent with objective results. For subjective discomfort, wearing the exoskeleton significantly impacted global discomfort. Also, it increased the local discomfort of the shoulders, waist, thighs, shanks, and feet/ankles. For new users, the risk of losing balance or falling may be increased when wearing an exoskeleton for non-target task behaviors (level walking/anterior load), and caution is recommended when the anterior load exceeds 5% BW. The proposed strategy for assessing human gait, balance, and discomfort in wearable chairs may be applied during the iterative design of the product. These controls will help develop training programs and implementation guidelines for this exoskeleton type.