Document Type


Degree Name

Master of Kinesiology (MKin)


Kinesiology and Physical Education


Faculty of Science

First Advisor

Michael Cinelli

Advisor Role



Background: Vision will guide the actions and behaviors that allow us to circumvent environmental obstacles. When passing through a gap, individuals will consistently elicit a shoulder rotation (SR) if the gap is 1.4 times their shoulder width (SW) or narrower, with this behaviour being produced under various environmental conditions. Although a few studies have investigated perceptual predictions regarding gap passage, the effect of physical activity and the differences between trained and untrained athlete’s behaviours has not been examined. This study investigated the perceptual judgements of non-athletes and varsity athletes regarding the action they would utilize to pass through a dynamically converging gap, and whether varsity athletes experienced any sport-specific benefits from a bout of physical activity.

Methods: Part 1) Eleven non-athletes walked (in VR) along a 7.5 m path while two avatars moved towards them on converging angles, creating perceived aperture widths of 0.8, 1, 1.2, 1.4, 1.6, and 1.8 x SW at the theoretical time of crossing. At 2 seconds prior to contact the screen went blank and the subjects identified whether they would rotate their shoulders to pass through the two or not. The non-athletes completed the study on two counterbalanced days, the exercise day involved a 14-minute exercise protocol (a 2-min warm-up, 10-min graded exercise bout, and a 2-min cool down), before repeating the task again. On the rest day participants sat quietly for 15 min before competing the task a second time. Part 2) Eighteen varsity athletes were randomized into an exercise or rest group. Both groups completed a single protocol from Part 1 (either the exercise or rest day).

Results: Both the non-athletes and varsity athletes’ perceptions were modulated to body-scaled judgments, such that smaller apertures were perceived to require significantly more rotations then larger ones. After exercise, the non-athletes critical point became more conservative (from 1.13 to 1.25 x SW), while the varsity athletes critical point got closer to their true SW (from 1.21 x SW to 1.17 x SW). Exercise had no effect on non-athlete’s response time (p=.47) or accuracy (p=.22) but shortened the varsity athletes response time (p=.033) and improved their accuracy (p=.046) from 69% to 82% correct perceptual judgements.

Conclusion: Overall, the results of the current study demonstrated that both non-athletes and varsity athletes successfully modulated their perceived SRs to gap width. It is possible the arousal following physical activity allowed the athletes enhanced visuomotor skills to be transferable to the current task by making it more sport-specific. The results from this study provide insight as to how individuals perceptually circumvent apertures without producing actions and provides further understanding as to how perceptions and actions work together to guide locomotion.

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