Master of Science (MSc)
Kinesiology and Physical Education
Faculty of Science
Dr. Michael Cinelli
Walking and navigating through cluttered environments is a task that people do almost automatically while completing multiple cognitive and motor tasks simultaneously. Vision plays an essential role in adaptive locomotion as it allows individuals to make anticipatory actions (i.e., alter trajectory and/or gait speed) to successfully avoid oncoming collisions (Cinelli et al., 2008; Patla, 1997). To initiate a behaviour change at the appropriate time, humans rely on optical variables such as time-to-contact (TTC) (Cinelli & Patla, 2007). After determining when to initiate an avoidance behaviour, it is thought that humans maintain a protective zone (i.e., safety margin) by controlling the minimum clearance distance between them and an approaching obstacle or person (Gérin-Lajoie et al., 2005). Although it has been demonstrated that there are significant cognitive demands to performing various locomotor tasks, more research is required to fully understand the effects of complex tasks (similar to everyday life) on human collision avoidance behaviours. As such, the purpose of this thesis was to examine the action strategies employed by young adults (with and without athletic training) while avoiding a virtual pedestrian (VP) approaching on a 45º under attentionally demanding conditions. Avoidance behaviours of young adults from the general student population were observed to gain a fundamental understanding of young adults’ collision avoidance behaviours during a complex task (Study 1). Then, using the same paradigm, young adults from the general student population (controls) were compared to collision sport athletes to examine whether sport-specific training influences one’s collision avoidance strategies (Study 2). Controls (N=21, 22.9±1.9 yrs, 11 males) and specifically trained athletes (N=18, 20±1.5 yrs, 7 males) were immersed in a virtual environment using the HTC VIVE Pro2 headset and were instructed to walk along a 7.5m path towards a goal located along the midline. Two virtual pedestrians (VP) positioned 2.83m to the left and right of the midline approached participants on a 45º angle at one of three speeds, 0.8x, 1.0x, and 1.2x each participants' average walking speed. Participants were instructed to walk to a goal without colliding with the VP. Participants performed a secondary task, where they reported whether a shape changed above the VPs' heads. Using the position of the VP and the participant, avoidance behaviours of time to first avoidance behaviour and minimum clearance were examined. Further, the percentage of correct responses on the secondary task were recorded. Results from both studies revealed that young adults (regardless of training) did not modulate their time of avoidance to the VP approach characteristics (i.e., avoided at the same time regardless of condition), however, both groups controlled minimum clearance to maintain a consistent margin of safety after a behaviour was initiated. Interestingly, it was found that sport-specific training did not influence minimum clearance, suggesting that training does not impact one’s personal space. Despite having similar action strategies, athletes were more variable in their behaviours and performed significantly better on the secondary task which suggests that athletes may be more adaptive and may perform better on attention tasks compared to controls. Similarities in the avoidance behaviours between the two groups may be a result of the task lacking sport-specificity or due to the predictability of the task.
Thompson, Brooke J., "Action strategies of young adults during an attentionally demanding collision avoidance task in virtual reality" (2023). Theses and Dissertations (Comprehensive). 2579.
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