I always like to use shortcuts to make quick calculations.
One example is driving a car in USA and Canada (Imperial vs metric)
To convert mph to kph, or simply miles and kilometers, I use factors of 0.6 and 1.6.
For example, 100 kph is 100 x 0.6 or 60 mph. The speed limit is traditionally 90 kph, or 54 mph.
That’s right, truncate the last digit (the zero) and multiply by 6.
Conversely, 50 mph is 50 x 1.6 or 80 kph.
Adjusting Wind for Sprints
I don’t necessarily agree on how the IAAF calculates the wind for 100, 200, LJ and PV. I’ve discussed that in several past articles.
But I have used a quick and dirty method for years, and it was just solidified in a recent paper (I’ll get to it in a minute)
My method was adding or subtracting 0.1 (one-tenth of a second) for every 1.0 m/s (meters per second) of a second for positive or negative wind.
So, a 10.00 100 meters with a +2.0 m/s wind is roughly 10.20.
A 10.00 100 meters with a -2.0 m/s wind is roughly 9.80.
I use this method especially when I am trying to find the 4 fastest guys for the relay pool (though I have to admit, fastest 100m times is one factor of many – the ability to handle the baton, team chemistry, curve running ability, ability to run 130m, etc. are other factors to consider)
Take a look at this paper, online at http://iopscience.iop.org/0143-0807/34/5/1227/
In On the performance of Usain Bolt in the 100m Sprint by J. J. Hernandez Gomez, V. Marquina and R. W. Gomez, EUROPEAN JOURNAL OF PHYSICS, Eur. J. Phys. 34 (2013) 1227–1233, they say a benchmark of 9.68 (0.0) gives 9.58 (+0.9) and 9.46 (+2.0) at those speeds.
NOTE: It is worth noting that their model works only for short sprints, as per their discussion.
It’s fairly close to my guestimate if adding 0.1 sec for every 1.0 wind, don’t you think?
It’s hard to believe breaking the world record by 0.01 (along with big paychecks!) is highly affected by wind of up to 2.0 m/s, which can give a 0.20 second advantage?
But at the end of the day, “drag” is highly affected by altitude (less drag) and wind (+/- drag). Again, I am only referring to short sprints and high speeds.
I won’t even talk about the fast Mondo tracks! Save that story for another day!
Jimson Lee
Latest posts by Jimson Lee (see all)
The estimations closer are around+ 0.10 seconds advantage for +2.0 wind and -0.14 disadvantage for -2.0 wind(the negative wind is worst in comparison)
My estimation is that one meter per second represents about three hundredths of a second.