A STUDY WITH PROBLEMS
Zachry, T., Wulf, G., Mercer, J., & Bezodis, N. (2005). Increased movement accuracy and reduced EMG activity as the result of adopting an external focus of attention. Brain Research Bulletin, 67, 304-309.
This investigation was supposed to contrast internal and external mental focus in the performance of a modified two-phase motor skill, shooting a basketball free throw. Ss performed 10 trials of an internal focus (snapping of the wrist in the follow-through), and an external focus (concentrating on the center of the rear of the hoop). The modification of the basketball throw was the experimenter controlling the cadence by directing "get set" and "go" in the timing of the preparation and initiation of the skill.
Free throw accuracy was greater under the external focus (25.6%) than under the internal focus (20.9%). EMG activity of the biceps and triceps muscles was lower in the external condition than in the internal condition.
However, the authors in their conclusions make a grand intellectual jump in generalizing these results to other activities (e.g., endurance performances). Some factors need to be considered before treating this study as the defining, all-encompassing description of mental focus in physical performance.
- The skill performed in this investigation is a two-phase motor skill, which is executed in a very short time. For such "basic" activities, external focus is important for the imagery used to map the succeeding response. The literature is consistent in this finding. However, in other classes of activity, internal focus is more important than external focus.
- The skill in this case was a modified skill because the intrusion of the experimenter in directing the skill preparation and movement initiation altered the timing of the complete skill (preparation + execution) that would occur normally. That modification would make the skill more novel than if a normal free throw were attempted. Consequently, Ss would be novices in the situation and activity, meaning that some adaptation (learning, habituation) would occur during the trials as they became used to the experimenter's intrusion into the more traditional activity. It is hard to speculate what effect that adjustment behavior would have on the actual behavior in the study.
- The focus of attention was one of direction (center of the hoop) in the external focus and localized post-activity (snapping the wrist in the follow-through) in the internal focus. These two forms of foci are not true tests of internal vs. external focus in the imagery and goal-setting literature involving motor skills and movement activities. They are very restricted elements in a complex environmental situation. They could be too restrictive to produce any performance improvement. How an internal focus on a post-ball-release movement segment would improve the movement elements before that focus is hard to imagine. A better test of the more traditional versions of internal and external focus might have been a) in the internal condition feel the smoothness of the total movement, and b) in the external condition see yourself shooting a smooth movement as if you were watching yourself from a spectator's viewpoint.
- The actual skill itself is an accuracy skill, the biomechanics of which requires the peak forces (but they are not maximal forces) to occur all at the same time. In a maximum effort skill, peak (maximal) forces should occur in sequence. There is the possibility that the components of effective focus between accuracy and maximum effort two-phase motor skills differ.
- The role of thinking during the execution of a two-phase motor skill should be considered. The literature has consistently shown that thinking during execution causes performance to be worsened due to the phenomenon of "cognitive interference". Thinking during performance was part of this study.
- Other elements of the study should also be questioned (e.g., what if Ss had been given 100 trials in each condition under the experimenter-intrusive circumstance before measures were taken) but will not be entertained here.
Implication. While this study might be considered as supporting the contention that an external focus of attention is the best imagery to employ when preparing for a two-phase motor activity, the actual implementation of those factors is questionable. It is possible to interpret this study alternatively as evaluating what are the accumulated effects of a number of factors that are likely to cause a modified free-throw shooting skill to deteriorate. Nothing concerning performance enhancement is shown in this study, despite the leap of faith of the authors in their sweeping generalizations at the end of the article.
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