(1) Background: Healthcare workers are highly affected by work-related musculoskeletal disorders, particularly in the lower back, neck and shoulders, as their occupational tasks expose them to biomechanical constraints. One solution to prevent these musculoskeletal disorders may be the use of a passive exoskeleton as it aims to reduce muscle solicitation. However, few studies have been carried out directly in this field to assess the impact of the use of a passive upper limb exoskeleton on this population. (2) Methods: Seven healthcare workers, equipped with electromyographic sensors, performed a tool cleaning task with and without a passive upper limb exoskeleton (Hapo MS, Ergosanté Technologie, France). Six muscles of the upper limbs were analysed, i.e., anterior deltoid, biceps brachii, pectoralis major, latissimus dorsi, triceps brachii and longissimus thoracis. A subjective analysis of the usability of the equipment, the perception of effort and discomfort, was also carried out using the System Usability Scale and the Borg scale. (3) Results: The longissimus thoracis was the most used muscle during this task. We observed a significant decrease in the muscular solicitation of the anterior deltoid and latissimus dorsi when wearing the exoskeleton. Other muscles were not significantly impacted by the device. (4) Conclusions: the passive exoskeleton used in this study allowed the reduction in muscular load on the anterior deltoid and latissimus dorsi without negative effects on other muscles. Other field studies with exoskeletons are now necessary, particularly in hospitals, to increase our knowledge and improve the acceptability of this system for the prevention of musculoskeletal disorders.

Contact robots are increasingly used to assist humans in physical training and manufacturing tasks. However, their effectiveness is currently limited as control methods focus on system performance without considering the upcoming human user’s control. Here, we present a differential game-based controller for contact robots ensuring optimal interaction by predicting human motor control over their finite planning horizon. Using this model-predictive game (MPG) controller, we investigated human-robot co-adaptation in experiments, demonstrating that: (a) MPG interaction remains stable while reducing human effort; (b) the robot adapts to humans, identifying time-consistent individual interaction behaviors; (c) humans adapt to the robot, and their behavior can be modulated through an assistance meta-parameter adjusting the robot’s propensity to minimize human effort. These findings indicate that humans understand and adapt to a partner’s control strategy aligning with game theory principles. Furthermore, the assistance meta-parameter’s ability to guide humans toward specific interaction behaviors enables versatile robot-assisted systems for physical training and rehabilitation.

Eccentric finger movements have been identified as risk factor in the injury mechanism of pulley ruptures during climbing. So far, they have mainly been associated with inadvertent events. Whether eccentric movements also occur as regular motion patterns was not assessed. Main purpose of this study was to examine eccentric finger movements during typical climbing tasks. Therefore, kinematics and interaction force of eleven elite climbers was recorded during a sequence of four climbing moves. Participants were instructed to use crimp, half-crimp, open-hand grip and campusing. Change of flexion angle in the proximal interphalangeal (PIP) joints from the start to the end of the holding phase (ΔPIP_P2) was calculated. Mean ΔPIP_P2 was -1.5° (SD 6.6°), 0.2° (5.1°), -2.9° (3.4°) and -6.0° (9.6°) for the open-hand, half-crimp, crimp and campusing task, respectively, whereby negative values represent eccentric movements. Eccentric finger joint movements (ΔPIP_P2 < 0°) during the holding phase were very common (59-73%) across all grip types. The loading rate was highest during campusing and lowest using the crimp grip. Climbers exhibit eccentric finger movements not only during accidental slips or when fatigued, but also as consistent patterns. Further research is needed to assess whether these differences are associated with an individual's risk of pulley injury.