Effects of a Back-Support Exoskeleton on Pelvis-Thorax Kinematics and Coordination During Lifting

We assessed the effects of a commercially available passive back support exoskeleton device on pelvis thorax kinematics and coordination. Eight male participants performed randomized block trials of 8 freestyle, symmetrical lifting tasks of a 13 kg container with or without use of the device. We obtained whole body kinematic data using an inertial motion capture system. We used Principal component analysis (PCA) to discern angular position and velocity waveform variations between conditions and assessed inter-segmental coordination using continuous relative phase measures. For joint angular position, only 1 PC exhibited statistical significance across conditions. This PC, which explained 10% of the loading vector variation, was interpreted as a phase shift feature. For joint angular velocity profiles, 2 PCs statistically differed between conditions. We interpreted these PCs as local magnitude difference features, particularly at the initial portion of the lift cycle. We did not detect a significant main effect of device usage or lifting phase on pelvis-thorax coordination. Our preliminary results suggest that use of a passive back support exoskeleton changes joint kinematics, but not inter-segment coordination during performance of a lifting task. These results may help understand device usability and interaction.