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Neil Arun Tolani
"The Biomechanics of Walking Backwards"
Sponsor: Rodger Kram, Assistant Professor of Integrative Biology

• Project Description
• Scholar's Photo
• Scholar's Journal

Neil's project will contribute to our understanding of the biomechanics of human locomotion. By studying backwards walking using human subjects on a treadmill, he hopes to discover how the inverted pendulum mechanism involved in walking is affected by reversing the direction in which human beings normally move. Through further quantitative analysis, Neil intends to determine which biomechanical factors set the metabolic cost of normal walking. The results of his research will have relevant implications for physical therapists and gait-disabled persons, for whom backwards walking is often used as a rehabilitation technique. This project will also help further prepare him for his intended career in biomedical research.

It is a little too ironic that the words "walking backwards" appear in the title of my project. For some time, the progress of my project was not moving in the forward direction. Of course, neither was it traveling in reverse; but it felt like for every three steps I advanced, I took two steps back.

Studying backward walking is a novel task at the UCB Locomotion Lab; as far as we know, there is not even any literature about how long it takes for human subjects to become acclimated. I would be in charge of performing precursor experiments, before I could even begin my proposed project of studying the biomechanics of walking backwards. In order to determine when a subject actually adjusts to walking backwards, I took a pool of five subjects and asked them to walk backwards at 1.00 meter/second for ten minutes. These subjects were individually filmed at high speed (200 fields/sec) with reflective markers on their heel and toe.

Next it was my chore to examine the films. I looked for the exact field that the toe struck the ground and the exact field that the heel came off the ground. With this information, I could calculate kinematic variables like time of contact (tc), stride time (st), and stride frequency (sf). When these variables settle to a steady state, the subject has become habituated to walking backwards. I aimed to look at the first ten strides of each minute, for each of ten minutes, for all five subjects. Doing the math, this equals 605 toe strikes, 550 heel offs, and countless hours of work! On top of this, I realized that the data was inconclusive and that a larger pool of subjects was needed.

I persevered, however, and eventually collected the data I needed. I currently am making excellent progress on my proposed project. We have an adage in science: take the estimated time to complete a project and multiply that by pi to get a more realistic time of arrival. In hindsight, I realize that each obstacle in my path made me stronger and more prepared for the next one. In any case, I should feel fortunate--I know a graduate student who wants to study the biomechanics of running in circles.