Motor learning without physical practice: The effects of combined action observation and motor imagery practice on cup-stacking speed

The Effects of Motionless Interventions Based on Visual-Auditory Instructions With Sonification on Learning a Rhythmic Motor Skill

Our aim in this study was to investigate the effects of motionless interventions, based on visual-auditory integration with a sonification technique, on the learning a complex rhythmic motor skill. We recruited 22 male participants with high physical fitness and provided them four acquisition sessions in which to practice hurdle running, based on a visual-auditory instructional pattern. Next, we divided participants into three groups: visual-auditory, auditory, and control. In six sessions of motionless interventions, with no physical practice, participants in the visual-auditory group received a visual-auditory pattern similar to their experience during the acquisition period. The auditory group only listened to the sound of sonified movements of an expert hurdler, and the control group received no instructional interventions. Finally, participants in all three groups underwent post-intervention and transfer tests to determine their errors in the spatial and relative timing of their leading leg's knee angular displacement. Both visual-auditory and auditory groups had significantly less spatial error than the control group. However, there were no significant group differences in relative timing in any test phase. These results indicate that the use of the sonification technique in the form of visual-auditory instruction adapted to the athletes' needs benefitted perception-sensory capacities to improve motor skill learning.

Observing an expert's action swapped with an observer's face increases corticospinal excitability during combined action observation and motor imagery

This study aimed to examine whether observing an expert's action swapped with an observer's face increases corticospinal excitability during combined action observation and motor imagery (AOMI). Twelve young males performed motor imagery of motor tasks with different difficulties while observing the actions of an expert performer and an expert performer with a swapped face. Motor tasks included bilateral wrist dorsiflexion (EASY) and unilateral two-ball rotating motions (DIFF). During the AOMI of EASY and DIFF, single-pulse transcranial magnetic stimulation was delivered to the left primary motor cortex, and motor-evoked potentials (MEPs) were obtained from the extensor carpi ulnaris and first dorsal interosseous muscles of the right upper limb, respectively. Visual analogue scale (VAS) assessed the subjective similarity of the expert performer with the swapped face in the EASY and DIFF to the participants themselves. The MEP amplitude in DIFF was larger in the observation of the expert performer with the swapped face than that of the expert performer (P = 0.012); however, the corresponding difference was not observed in EASY (P = 1.000). The relative change in the MEP amplitude from observing the action of the expert performer to that of the expert performer with the swapped face was positively correlated with VAS only in DIFF (r = 0.644, P = 0.024). These results indicate that observing the action of an expert performer with the observer's face enhances corticospinal excitability during AOMI, depending on the task difficulty and subjective similarity between the expert performer being observed and the observer.