Evaluating Gait Stability and Muscle Activation in Different Hand Holding Conditions Using the Robotic Walker-mTPAD

While walkers are used as mobility aids for different gait impairments, little is known about the factors that affect the performance of such aids. Therefore, we investigated the impact of arm-holding conditions on gait stability and muscle activation. We used surface electromyography (sEMG) sensors on specific arm and leg muscles while the users took laps with a robotic walker, the mobile Tethered Pelvic Assist Device (mTPAD), on an instrumented mat. Eleven participants without gait disorders walked with and without a 10% body weight (BW) force applied on the pelvis in the following three configurations: (i) while gripping the walker's frame, (ii) while using an armrest with their arms at a 90∘ angle, and (iii) while using an armrest with their arms at a 130∘ angle for 5 min each. Our results showed that when applying a force, the users changed their gait to increase stability. We also discovered differences in muscle activation based on the user's specific arm conditions. Specifically, the 130∘ condition required the least muscle activation, while gripping the walker's frame increased specific muscle activation compared to 90∘ and 130∘. This study is the first to evaluate how arm-holding and external loading conditions alter gait and muscle activations using the mTPAD.