GL Bruxelles m100m - Usain Bolt 9.77

[imaginative]

There is also something fishy about the wind reading in the Brussels women's 200m. The Omega wind reading was displayed on TV at about 20.1 seconds after the race start, when the runners were still about 20m from the finish line! I believe that IAAF rules (163.8) require that, in the 200m, "the wind velocity shall be measured for a period of 10 seconds commencing when the first runner enters the straight." The first runner to enter the straight (at the blend lines) was Kerron Stewart at about 14.0 seconds. So, in this case, the wind reading was displayed only 6.1 seconds after the first runner entered the home straight!

If I understand this correctly, it implies another complication with
wind-readings: There can be considerable non-overlapping parts of the
``measurement frame'' and the time each individual runner spends on the
straight, which in turn can make the wind-reading very misleading.
(Consider e.g. a wind that averages 2.5 m/s when the winner is actually on
the straight, and 0 m/s in the time between his crossing the line and the
10s expiring: with 8s or less on the straight, the reading is <= 2 m/s.)

In extreme cases, say Bolt vs. an ``olympic tourist'', the last placer may
less than half his time on the straight within the measurement frame.
(Example: Bolt enters the straight 3.5 seconds ahead, the tourist later
spends 14 seconds on the straight => Only the first 6.5 out of 14 seconds
where measured.)

(The corresponding problem in the 100m is much smaller for, at least,
world-class runners.)

[Charley Shaffer]

If I understand this correctly, it implies another complication with
wind-readings: There can be considerable non-overlapping parts of the
``measurement frame'' and the time each individual runner spends on the
straight, which in turn can make the wind-reading very misleading.

I agree; that's one reason why taking "adjusted" or "basic" times to 1/1000 second is going too far, and why we should not take the "adjustments" to 1/100 too seriously.

Per IAAF rules, the wind measurement period will include some time after a world-class runner running a good time will have finished. This is especially true in the 200m, since most straights are less than 100m (typically 84.39m), but 10 seconds of timing on the straight is mandated.