Cortical Processing and Lower Limb Muscle Activity Increase During Bodyweight Supported Treadmill Locomotion Underwater Compared to On-Land

Body weight support (BWS) systems are commonly used during gait rehabilitation to assist individuals with motor impairments. Traditional approaches involve mechanical unloading through overhead harness systems or buoyancy-assisted underwater walking, each providing unique biomechanical and neuromuscular advantages. The effects of external loading conditions on neural and muscular dynamics are not well understood. We evaluated electrical brain and lower limb muscle activities during treadmill walking with mechanical BWS on-land and underwater. Here, we show that contrasting BWS mechanisms modulate frontoparietal electrocortical spectral power and lower limb myoelectric activity. Underwater walking reduced frontoparietal alpha (8-13 Hz) and beta band power (13-30 Hz) and increased rectus femoris, biceps femoris, tibialis anterior, and lateral gastrocnemius muscle activities compared to walking on-land treadmill, with and without mechanical unloading. Discernible changes in sensorimotor processing and muscle activations during bodyweight supported treadmill walking can provide objective biomarkers to help refine personalized rehabilitation strategies.