Changing one’s focus of attention alters the structure of movement variability

摘要

Substantial evidence supports the beneficial effect of an external (vs. internal) focus of attention on task performance during goal-directed movements. Counter-intuitively, an external focus has also been shown to increase joint-level movement variability. ObjectiveTo determine whether shifting attentional focus can alter the structure of movement variability, thereby offering a probable mechanistic explanation for how adopting an external focus of attention might confer its benefits. MethodsThirty-five healthy adults (age 23–55) performed unipedal hopping under three different attentional foci: natural (no directed focus), internal focus, and external focus. Uncontrolled manifold analysis was used to examine the structure of movement variability with respect to stabilization of leg orientation and vertical leg length during hopping. Takeoff/landing event bin and stance phase integrals of performance-irrelevant and performance-destabilizing variability were compared across focus conditions. ResultsAccuracy of hopping in place improved with both external and internal foci compared to the natural condition (.004?≤?p?≤?.035). External focus, to a greater degree than internal focus, destabilized leg orientation at takeoff and landing compared to the natural condition (.001?≤?p?≤?.038). External focus increased – but internal focus decreased – leg length stabilization throughout stance compared to the natural condition (p?