The autonomy and focus of attention strategies under distraction: Frequency and sample entropy analyses in a dynamic balance task.

An external focus of attention has been shown to be effective in balance tasks. However, replication in applied settings is limited. The OPTIMAL theory proposes that a combination of autonomy and external focus increases focus to the task goal, and therefore more effective than external focus alone. However, research suggests that the combined effect is limited in discrete skills, and the increased focus effect is only reported by subjective assessment. The present study examined the effect of the combined strategy and its effect of "increased focus" compared to external focus and control groups under distraction. In experiment 1, participants (N = 60) practiced eight 35 s trials on a stabilometer followed by a 10 min-delayed retention test and an auditory distraction transfer test. The combined group chose a tape color to place on a stabilometer and was told to "keep the tapes parallel to the floor," the external focus group was yoked with the combined group, and the control group was told to "do your best". Performance was measured in Root Mean Square Error (RMSE). The increased focus effect was examined by both subjective (distraction score, a question about participants' perceptions) and objective (Mean Power Frequency, MPF, Sample entropy, SampEn) methods. Although participants improved significantly (p < .05), group differences were not observed during retention (p's > 0.05). An increased focus effect of the combined effect was not observed in any variables (p's > 0.05). In experiment 2, the practice duration was extended to replicate previous study designs (i.e., 90s trials; 2 days of practice; 24 h retention test; the number of participants). Consistent with experiment 1, group differences were not evident in RMSE, SampEn, and MPF (p's > 0.05). We suggest that autonomy may be required to be task-relevant, and simply telling to do best may be as useful as external focus or combined strategies in a continuous balance task. Further, the analysis showed that SampEn increased on Day 1 but decreased on Day 2, and MPF decreased within a session, but the average MPF increased by the day. Potential explanations and future directions when utilizing these metrics are discussed.