This article is guest blogged by University lecturer Dr. Vassilios McInnes Spathopoulos, author of An Introduction to the Physics of Sports
He also wrote Windy Records in Track & Field and I wrote Curve Running – The Ultimate Guide so this is a great article on WIND and CURVE.
The Effect of Wind on Curve Running
The effect of wind on the performance in the 100m dash has been discussed in a previous article of mine. From a physics point of view the analysis is quite straightforward, assuming that the athlete experiences an almost constant component of wind when running in a straight line. A tailwind component will have the effect of reducing the air resistance (drag) and therefore making the run slightly easier for the athlete. So at zero altitude a maximum legal wind will approximately shave off 0.1s from the overall time.
When running in a curve, as in the 200m event, things become a little more complicated. Let us see what actually happens. The IAAF rules state that it is only the component of wind along the final straight that is measured (from the moment that the first athlete enters it, for 10s) and this must not exceed a maximum tailwind of 2m/s. Nothing is stated or known about the wind experienced by athletes during the first half of the race. As the angle of their run relative to the wind direction is constantly changing, so will the value of air resistance that they experience during the first 100m.
Furthermore, different wind conditions will register as being the same when measured by the wind gauge positioned on the final straight. So for example, a straight 2m/s tailwind, will register the same as a 4m/s crosswind coming at an angle of 60 degrees. It is pretty obvious, that the resistance experienced by the athlete during the first half of the race will be different for both cases.
Finally, due to the curvature, the effect of the wind will also depend on the lane at which one is running, something not seen for the 100m dash case. It turns out that runners in the outside lane actually have an advantage, as the overall wind resistance is reduced.
Has anyone been able to put numbers to all of this? It turns out that compared to the 100m case, there have been fewer studies performed for the 200m. In one such research effort [1], it has been estimated that for a wind blowing down the straight at the maximum legal limit of 2m/s, the actual overall average tailwind experienced over the 200m is approximately 0.95m/s. Also, as different wind conditions can produce the same readings from the wind gauge in the final straight, athletes running in theory under the same conditions can experience time differences due to wind of up to 0.5s. A good combination would be for a 4m/s wind coming from behind at an angle of 60 degrees. This would give a time advantage of about 0.3s, certainly not at all negligible! Finally, both this study and one described in [2] predict an advantage for those running in the outside lane. In terms of exact time, this will depend on the prevailing conditions, but in any case can be quite considerable.
Overall then, it seems as if a strict rule has been imposed on the conditions of a race, conditions for which in the best case, we only have knowledge of for half the race duration. With all the technology nowadays available, it might be time to reconsider offering athletes a more objective deal.
About the Author
Dr. Vassilios McInnes Spathopoulos graduated from the University of Glasgow (UK), with a joint honours degree in Aerospace and Electronic Engineering, in 1995. The following year he completed a MSc course in Flight Dynamics at Cranfield University (UK). In 2001 he obtained his PhD from the University of Glasgow, conducting research on the validation of a rotorcraft mathematical model by means of flight testing a gyroplane. He teaches undergraduate subjects at the Department of Aircraft Technology, at the Technological Education Institute (TEI) of Chalkis, Greece. His research interests include the aerodynamics of sports balls and improving engineering education.
An Introduction to the Physics of Sports (Kindle ebook)
References
[1] Quinn, Mike D., “The Effects of Wind and Altitude in the 200-m Sprint”, Journal of Applied Biomechanics, 2003, Vol. 19 Issue 1, p49
[2] Mureika, JR, “Modeling wind and altitude effects in the 200-m sprint”, Canadian Journal of Physics, 2003, 81, 895-910
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Very instructive article, and nicely written.
I have always maintained that there should be two seperated wind gauges in the 200 metres, one at the 50 metre mark and one at the 150 metre mark, then the results are averaged.
Reason:A great many times I have run the 200 curve into a very strong head wind(prevaling north easterly wind in New zealand) only to be informed by the officials after the race that the wind gauge recorded a tail wind at the 150 mark due to a swirling wind along the straight.Many possible 200 metre records are disallowed because of the failure two have two wind gauge readings.With modern technology there could also be far more accurate wind readings in the 100 metres, because recording the wind for 1/10th of a second at the 50 metre mark is somewhat archaic.
Good to know that you basically have the same opinion, although viewing it from a different angle!