Gaze behavior of elite basketball athletes was determined as they performed 10 accurate and 10 inaccurate free throws (FTs) to a regulation basket wearing an eye tracker that permitted normal accuracy. Experts (mean FT = 78%) differed significantly from near experts (mean FT = 56%) in having a longer fixation on the target combined with an earlier fixation offset during the shooting action. These results, which depart from current models of near aiming, are tentatively explained using a location-suppression hypothesis. During the early phases of the aiming action, a fixation of long duration is needed on a specific target location. As the aiming action is then performed, vision appears to be a liability and is suppressed.

Spatio-temporal gaze behaviour patterns were analysed as normal participants wearing a mobile eye tracker approached and stepped over obstacles of varying height in the travel path. We examined the frequency and duration of three types of gaze fixation with respect to the participants' stepping patterns: obstacle fixation (ObsFix); travel fixation (TravFix) (when the gaze is stable and travelling at the speed of whole body) and fixation in the 4-6m region (Fix4-6). During the approach phase to the obstacle, participants fixated on the obstacle for approximately 20% of the travel time. Only Fix4-6 duration was modulated as a function of obstacle height by regulating the frequency and reflected the increased time needed for detection of the small low contrast obstacle in the travel path. Frequency of ObsFix increased significantly as a function of obstacle height and reflected visuo-motor transformation needed for limb elevation control. Participants did not fixate on the obstacle as they were stepping over, but did the planning in the steps before. TravFix duration and frequency was constant while Fix4-6 duration was higher in the step before and step over the obstacle reflecting visual search of the landing area for the lead limb following obstacle avoidance. These results clearly show that obstacle information provided by vision is used in a feed-forward rather than on-line control mode to regulate locomotion. Information about self-motion acquired from optic flow during TravFix can be used to control velocity of locomotion.

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The authors provide evidence that choking under pressure is associated with changes in visual attention. Ten elite biathlon shooters were tested under separate low-pressure (LP) and high-pressure (HP) conditions after exercising on a cycle ergometer at individually prescribed power output (PO) levels of 55%, 70%, 85%, and 100% of their maximum oxygen uptake. The authors determined difference scores by subtracting each athlete's score in the LP condition from his or her score in the HP condition for heart rate (d-HR), rate of perceived exertion (d-RPE), cognitive anxiety (d-CA), and cognitive worry (d-CW), and final fixation on the target or quiet eye gaze (d-QE). Using regression analysis, the authors determined predictors of accuracy for each HP PO level. At PO 55%, the authors found 3 predictors (d-HR, d-RPE, d-QE) that accounted for .62 of the adjusted R2 variance. Accuracy was higher when d-QE was lower and d-RPE and d-HR were higher than the values found in the LP condition. At PO 100%, however, an increase in d-QE and d-RPE accounted for .58 of the adjusted R2 variance. Accuracy was dependent on an increase in external focus (positive d-QE) independently of heart rate. At the highest PO level, directing visual attention externally to critical task information appeared to insulate the athletes from choking under HP.

Spatial-temporal gaze behaviour patterns were analysed as normal participants wearing a mobile eye tracker were required to step on 17 footprints, regularly or irregularly spaced over a 10-m distance, placed in their travel path. We examined the characteristics of two types of gaze fixation with respect to the participants' stepping patterns: footprint fixation; and travel fixation when the gaze is stable and travelling at the speed of whole body. The results showed that travel gaze fixation is a dominant gaze behaviour occupying over 50% of the travel time. It is hypothesised that this gaze behaviour would facilitate acquisition of environmental and self-motion information from the optic flow that is generated during locomotion: this in turn would guide movements of the lower limbs to the appropriate landing targets. When participants did fixate on the landing target they did so on average two steps ahead, about 800-1000 ms before the limb is placed on the target area. This would allow them sufficient time to successfully modify their gait patterns. None of the gaze behaviours was influenced by the placement (regularly versus irregularly spaced) of the footprints or repeated exposures to the travel path. Rather visual information acquired during each trial was used "de novo" to modulate gait patterns. This study provides a clear temporal link between gaze and stepping pattern and adds to our understanding of how vision is used to regulate locomotion.