A Wearable Haptic Feedback System for Arm-Swing Amplitude Modulation During Overground Walking in Older Adults

Reduced arm swing frequently occurs in older adults and is associated with declined gait performance. Experimental studies have demonstrated that restricting arm swing decreases stride length and walking speed, whereas deliberately increasing arm swing can improve these gait parameters. This study evaluated whether a wearable haptic feedback system could effectively increase arm-swing amplitude and assess its effects on spatiotemporal gait outcomes during overground walking. Using a within-subject repeated-measures design, twelve community-dwelling older adults (6 males/6 females; 75.8±6.5 years) completed three no-feedback conditions (Baseline, Exaggerated, Fast) and six feedback conditions varying Direction (Forward, Backward, Combined) and target Magnitude (+100%, +200% of the Baseline). The arm-swing angle was estimated in real time from upper-arm inertial measurement unit (IMU) sensors; targets were defined for peak Forward flexion and/or peak Backward extension, and vibrotactile cues were delivered when the corresponding peak failed to reach the target. The arm range of motion (ROM) increased significantly across conditions, with the largest increase during Feedback (+229%), exceeding Exaggerated (+120%) and Fast (+64%) (all p<0.001). Walking speed and stride length also increased during Feedback relative to the Baseline (p<0.001). Within feedback conditions, the arm ROM showed independent main effects of the Direction and Magnitude, whereas gait outcomes were primarily influenced by Direction. Arm-swing symmetry was largely preserved, with the smallest variability during Feedback. These findings support the feasibility of vibrotactile feedback to enhance arm swing and improve gait outcomes in older adults.