A question about the 40 Yard Dash...

A fair question Rock N Roll, when you consider that 40yds is 36.56 metres, it doesn’t do much to help the case for running 40yds in under 4.0 seconds. I believe, Bruny Surin covered 30m in 3.79s in the 100m final in Seville in 99’, which is one of the fastest of all time. That would only equal a 4.62s 40yd time: 3.79*36.56/30=4.61874 (please correct me if I am wrong). However I think it is more complex than that when comparing 40yd times to 100m times. For example, someone said in another thread that Carl Lewis did the 55m in 6.02s. That would be equivalent to about 4.00s for 40yds. Of course the fastest segment in a 100m race will be entered with a running start, but it makes me think that maybe a sub 4.0s 40 yd is possible. Just some thoughts.

earle, the math isn’t that easy since the person is acelerating (sp?). The final ten meters of the 40 is not equal to the average of the first 30. The runner is covering the distance at a much faster rate.

As explained by Silverback, earle’s calculations are off, because they are based on the assumption that the sprinter runs at the same speed from start to finish.

40y is 36.58m.

In the 1999 final Suring got to the 30m mark in 3.79 and to the 40m mark 0.89s later.

You therefore have to calculate 3.79 + 0.089*(36.58-30) = 4.38 sec for 40y.

If Carl Lewis ran 55m in 6.02s we can assume that his average speed between 40y and 55m should have been about 11.62m/s or 0.086 s/m (estimation based on his 1991 Tokyo splits). His 40y time would thus have been about 6.02 - 0.086*(55-36.58) = 4.44s.

In Tokyo, Lewis got to the 40y mark in about 4.47s, by the way.

Ben Johnson’s 1988 40y time would have been about 4.35s.
This is not using the often quoted 3.80s split for 30m, which appears to me to be a calculation error, but a corrected value of 3.76s. If you check out the 1988 splits (for example at http://desert.jsd.claremont.edu/~newt/track/splits/Seoul.html) you will see that the 30m time without RT is 3.63. If you add Ben’s RT of 0.132s to this you get 3.76 and not 3.80s. For the other splits the two times (with and without RT) all correspond properly.
This also shows that Maurice Greene’s Edmonton race is much more similar to Ben’s Seoul race than usually assumed. It is thus not correct to state that Greene was much faster in the beginning of the race while Ben caught up towards the end. Both races were actually very similar.

Corrected comparison between the two races:

Johnson 1988:Greene 2001:
1.83s 1.83s
2.87s 2.83s
3.76s 3.75s
4.66s 4.64s
5.50s 5.50s
6.33s 6.33s
7.17s 7.19s
8.02s 8.03s
8.89s 8.91s
9.79s 9.82s

The only significant difference left now is at the 20m segment, which I would attribute to an error.