Effect of attentional focus on muscles activations and their recruitment during learning a balance control task

In this pilot study we investigated the effects of external and internal focus of attention on motor learning and performance during learning a balance control task. Pilot experiments were conducted by instructing two groups of healthy students (right footed). In the external-focus condition, performers were conducted to focus on a marker on the wall in front of them whereas in the internal focus group, participants were instructed to focus on their feet. Participants performed a total of five trials on the balance board per session for five days as every two other days. In both of the foregoing conditions, muscle activations (EMG signals) of both sides of each participant were recorded. The vertical displacements of the balance board in the frontal plane were also recorded with a camera. In this study two indices were introduced. External focus Index (EfI) and Internal Focus Index (IfI). EfI is defined as the difference between RMS values of EMG signals of the right (dominant) and left side of the body, while IfI is defined as the difference between RMS values of EMG signals of the left (non-dominant) and right side of the body. Our preliminary results indicate that the balance controlling skill is positively correlated with EfI in the external focus group and with IfI in the internal focus group. These results indicate that balance control strategy that each group applied to increase balance control skill on Medio-lateral balance board may depend on the use of dominant or non-dominant side of the body. Furthermore, the balance skill in external focus group is more than internal focus group, but vice versa for muscle activation. This result clearly indicates that external focus of attention is more effective compared to internal one.