General Discussion Triathlon Talk » Aerodynamic drag impacts - running Rss Feed  
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2011-01-01 5:18 PM

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Subject: Aerodynamic drag impacts - running
Marathon training (solo) has given me plenty of time to think during those long runs......

So yesterday I was running into a 16mph headwind and started to think how much energy it really takes to overcome such a brutal wind. As it was unseasonably warm, I was wearing baggy running shorts and a loose fitting shirt (less than ideal from a Coefficient of Drag standpoint).

There are plenty of aerodynamic drag studies for cycling and even some for swimming, but very little that I could find for running. So I created a spreadsheet that calculates the Power due to aerodynamic drag while running.....see attached for ".jpg" screenshot of the spreadsheet.

Note that the calculations are just theoretical and I have no controlled experimental data (but it would be interesting to design an experiment). There are multiple real-life parameters not considered here. Calculations were performed using frontal body area, straight-on headwind and assumptions were made regarding Cd (Coeff. Drag) based on my approximated chest profile (see picture in spreadsheet). Also listed are 2 references for the Cd assumptions between tight vs loose clothing cases.

Interesting results from the calculations;
1) 0mph headwind at 8:54 consistent pace (my marathon target pace) shows "skin-tight" clothes to be 3.5 seconds faster per mile. This translates to 1min 32sec faster for a marathon.
2) 16mph constant headwind and 8:54 consistent pace, "skin-tight" clothes could be 11.7 seconds per mile faster than "loose" clothing.
3) 8:54 consistent pace with 16mph constant headwind wearing "loose" clothing calculates to 249 Watts from aerodynamic drag.
4) 0mph headwind with 8:54 consistent pace in "loose" clothes calculates to 6.48 Watts from aerodynamic drag.

Call me a tri-geek on holiday with too much time on my hands. What do you think....plausible results given the assumptions?

Let ‘em shake their heads at me while I rock the spandex during my upcoming marathon.



(Aerodynamic drag while running.JPG)



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General Discussion Triathlon Talk » Aerodynamic drag impacts - running Rss Feed