Fig. 3

Overview of the weight-shifting task and the vibration system. (Modified from Yasuda et al. [37]: The effect of a haptic biofeedback system on postural control in patients with stroke: an experimental pilot study. Somatosensory and motor research) [37]. a Participants were asked to stand with the feet 30 cm apart, and starting with their body weight shifted to the left side with the vibrating unit attached to the waist, and participants weight shift to the target position. Once the vibrations stopped, the activation of the vibrator was shifted to the opposite side. The time latency between users' movements and vibration was approximately 50 mm/s. b Vibration motors are mapped on a bony ridge (i.e., the bilateral anterior and posterior superior iliac spines) to convey vibrotactile stimulation. c The percentage of weight shifting was increased, based on the set Weber ratio (initial value: 0.05), without communicating this change to the participants