Sept. 3, 2019
Parkour wall climb: An abnormal snapshot of normal locomotion
Picture this scene from an action movie: a man is fleeing down a narrow dead-end alley. He leaps to scale the wall, grips the top, jumps on top of the building and completes his successful getaway. Climbing a wall, while seemingly impossible to most of us, is a common stunt among the parkour community.
Dr. John Bertram, PhD, along with Dr. James Croft, PhD, from Edith Cowan University, are collaborating to understand the strategies behind parkour movements and the way the brain reacts to control the leg in dynamic circumstances.
In John Bertram’s lab, Bertram and graduate student, Ryan Schroeder are using biomechanical analysis to study movement patterns in locomotion. They want to understand how people interact within dynamic environments. Surprisingly, focusing on the exceptionality of parkour movements helps explain normal patterns of locomotion by analyzing how the legs react in different environments.
“The human body has infinite leg control strategies and the brain selects the best strategy based on the presented environment. Studying movement in different contexts allows us to predict what leg control the brain will choose,” explains Bertram.
Rather than examine the leg’s natural response in running, Bertram and Schroeder are flipping the model and studying extreme cases such as parkour movements to better understand the limitations and opportunities of the leg.
“We are interested in parkour because these athletes use their legs like they’re running, but for something very different. It presents an opportunity to see how the physiology of leg control changes depending on the task. We study unusual locomotion, parkour, reduced gravity walking and running, in order to determine why normal locomotion is normal. That is, why is that particular movement strategy employed? We believe that fundamental understanding will be useful in developing non-intuitive interventions for gait pathology and rehabilitation,” states Bertram.
To examine the parkour wall climb, the team constructed a runway and a 3-meter plywood wall with force plates embedded where the athlete’s foot lands for take-off and contacts the wall. With help from the Perth Parkour Association, they gathered parkour athletes to complete sixty trials to collect data. The team filmed each runner from the start of the runaway to the impacts on both plates, allowing them to measure the movements and forces involved. The recordings showed that the athletes achieved the task of climbing the wall using a choreographed pattern of foot contacts and leg motions to propel themselves upward.
To test the findings, Schroeder built a computer simulation which determined that an intermediate run-up speed was an optimal tactic to efficiently convert energy from the run-up and use it to redirect off the ground for a successful liftoff. Both faster and slower run-ups actually increase the work needed to reach the top of the wall.
Impacts of study
The findings reveal how parkour athletes are able to adapt their leg movements and provides information on how they can improve their efficiency. In addition, this study provides clues on the constraints of the human leg, leg controls and the role of the environment.
The team plans further parkour studies with the goal of building an experimental parkour course where they can manipulate alternative tracks to understand the athlete’s movement control strategies.
Photo credit placed at the bottom of the picture
A parkour athlete performs a run-up and wall climb maneuver with one leg on the ground and one leg on the wall. The trajectory of the body center of mass is traced over time and foot contact positions (diamonds) are determined from force-sensitive plates embedded in the ground and wall. (Photo credit: James Croft)
John Bertram is a member of the McCaig Institute for Bone and Joint Health and he is a professor with the Department of Cell Biology and Anatomy in the Cumming School of Medicine and an adjunct professor with the Department of Comparative Biology and Experimental Medicine in the Faculty of Veterinary Medicine. He is the Director of the Biomedical Engineering Graduate Program and an associated research with the Centre for Bioengineering Research and Education.
Ryan Schroeder is a PhD Candidate in the Biomedical Engineering Graduate Program.
James Croft is a lecturer in Motor Control and Skill Acquisition at Edith Cowan University in Perth, Australia. He is also an alumnus of the University of Calgary.