This study aimed to investigate the effect of dynamic visual stimulation using augmented reality floor on lower extremity muscle activity and postural stability in normal adults.
A total of 30 adult male and female subjects in their 20s and 30s, who were physically and mentally healthy, were included in this study. They were able to meet the subject selection criteria, and all of them participated voluntarily. Furthermore, they agreed to the aim and procedures of the study.
In this study, an eight-channel wireless surface electromyography device(Desktop DTS, Noraxon, USA) was used to measure the activities of the lower-extremity muscles, such as the tibialis anterior, peroneus brevis, medial gastrocnemius, and lateral gastrocnemius, according to dynamic visual stimulation. For the measurement of postural stability, overall stability and the anterior-posterior and medial-lateral stabilities were measured using the Balance System SD(Biodex Medical Systems Inc., USA).
Each test was conducted thrice, and mean values were obtained. For the research material, statistical processing was performed using the SPSS software version 21.0 for Windows(SPSS Inc., USA).
The result of this study indicated that when the muscle activities were compared according to the speed of the dynamic visual stimulation, no significant difference was observed in the activities of the tibialis anterior in all speeds of the visual stimulation(p>.05). Furthermore, a statistically significant difference was observed in the muscle activities of the peroneus brevis in the non-moving and slow, non-moving and moderate, and non-moving and fast visual stimulation(p<.05). There was also a statistically significant difference in the muscle activities of the medial gastrocnemius in the non-moving and moderate and non-moving and fast visual stimulation(p<.05), and there was no significant difference when watching a slow visual stimulation(p>.05). Moreover, no significant difference was observed in the muscle activity of the lateral gastrocnemius in all speeds of the visual stimulation(p>.05). When the muscle activities were compared according to the direction of the dynamic visual stimulation, no significant difference was observed in the muscle activities of the tibialis anterior, peroneus brevis, and medial gastrocnemius muscles when watching the anterior-posterior and medial-lateral movements(p>.05). Further, there was a statistically significant difference in the lateral gastrocnemius activities between the movement directions(p<.05). When the postural stabilities were compared according to the speed of the dynamic visual stimulation, no significant difference was observed in the non-moving slow, moderate, and fast visual stimulation(p>.05). When the postural stabilities were compared according to the direction of the dynamic visual stimulation, a statistically significant difference was observed in the overall stability index when watching the anterior-posterior and medial-lateral movements(p<.01). There was also no significant difference between the anterior-posterior and medial-lateral stability indices according to the visual stimulation direction(p>.05).
The results of this study indicated that the activities of the lower-extremity muscle and postural stability changed according to the dynamic visual stimulation that changed the speed and direction of the virtual reality floor. It was also found that the characteristics of the dynamic visual stimuli can have different effects on posture control. Further research on dynamic visual stimulation using virtual reality floor is required to enable it to use in balance training and rehabilitation.