Effects of different verbal instructions on usage of haptic guidance

In sports and rehabilitation settings, although haptic guidance is a general method for facilitating motor learning, the effects of verbal instruction on motor learning remain unclear when using haptic guidance. This study thus investigated the influence of verbal instruction on a novel visuo-motor task presented before practice, while also implementing haptic guidance. Thirty participants, who performed a mirror drawing task, were randomly allocated to three groups: control-without augmented verbal instruction, HG-with relying (HG-with)-instructed to rely on guidance devices, and HG-without relying (HG-without)-instructed not to rely on guidance devices. We assessed the tracing time and error area of the mirror drawing task as performance measurements. The self-made guidance devices used in the practice session were constructed of 2-mm-thick cardboard and had a 5-mm-wide groove that matched the shape of the target figure. The tracing time in HG-with condition during the practice session (median = 66.5 s, IQR = 55.3-80.5 s) was significantly shorter compared with that in control condition (median = 132.5 s, IQR = 125.0-144.8 s) (p = .019). The error area (median = 585.0 mm2, IQR = 559-687.0 mm2) was also significantly larger in the HG-with condition than in control condition (median = 413.5 mm2, IQR = 350.5-494.0 mm2) (p = .029). Additionally, HG-with condition (mean = 46 %, SD = 12.3 %) showed greater improvement rate for tracing time from pre-test to post-test than HG-without condition (mean = 30 %, SD = 8.3 %) (p = .032). Our results suggest that, even if the same haptic guidance was implemented, visuo-motor task improvement was influenced by verbal instructions.