## Sunday, October 16, 2016

### Why Running on the Curve of a Track is Slower

Nick Baglieri
Professor Metzler
Physics 111
15 October 2016

Why is Running on The Curve of the Track Slower?
According to a study published in the Journal of Biology and to the testaments of most runners, sprinting on a curve is slower than sprinting on a straightaway. For example, if a 200 meter race was performed on a track with a 21 meter curve, it would be .12 seconds faster than a 15 m curve. 200 meter sprinters run .4 seconds slower on straight tracks than curved tracks.  “This decrease in maximum speed is related to the curvature of the track lane and can potentially result in one sprinter gaining an advantage of up to 0.12 s over a competitor in an adjacent inside lane.”

One attempted explanation has been by modeling a sprinter as a point mass moving in a circular path. When a runner runs straight, he/she exerts a vertical force on the ground, however on a curve, the runner exerts a lateral and vertical force that results in a resultant force vector. This lateral force generates a centripetal force for the runner. Centripetal force is required to change the angular momentum vector of the runner. The runner exerts the same resultant force regardless of the surface, so the vertical force exerted by the runner must be smaller on the curved surface. This increases the contact time with the ground, and decreases the impulse of the runner, making he/she run slower.

Source: http://jeb.biologists.org/content/210/6/971#F1