Track & Field
Photo Finishes

by
coachdeanhebert

I know that
most of you who read this aren’t sprinters and you may not even follow
track and field that much (if at all). For those who do, this one’s for
you.

We had a good
discussion about photo finishes and how it is determined who wins in those
close races. And given the “photo finishes” at the track &
field World Championships in Osaka this past week I thought I post this.

2007 IAAF World Championships 100 meter final photo.

This is an
actual photo from the electronic equipment used for photo finishes. It is a
high speed picture. The cameras are mounted about 10-12 feet above the track to
the outside (sometimes the inside). Notice the distortion of the runners. The
green vertical lines align with the torso of that runner as they crossed the
finish line. Torsos are timed, not arms, legs or heads. If you follow the line
to the bottom there is a scale of time. The big lines are in 10ths of seconds
(10.1 = 10 and 1/10 of a second). The smaller lines between are 100ths.
Official times are always rounded to the slower 100ths in track. So if that
green lands between the scale lines, it is read to the next slower line.

A couple other
tidbits:

In the upper left you see the date and the wind speed. It has to be less than
2.0 meters per second. 2.0 m/s or greater is considered “wind
aided”. That means the time is not eligible for record
purposes. In case you’re wondering, that is a very light breeze! In this
case it was a “minus” wind or a slight head wind of .5 m/s.

The table in
the lower left shows place, and final time. Also note the reaction time which
is measured electronically from the starting blocks. It is triggered by the
pressure applied to the starting blocks. The starters gun is electronically
connected as well. Most meets do not have the starting blocks wired. But, if
the starters gun is connected to the electronic timing/photo system it is
called Fully Automatic Timing (FAT). These are the only times that can be
recorded in 100ths. All other times have to be recorded in 10ths. Yes…
that means that even though your wrist chronograph stops on 10.42 seconds it
would have to be read and recorded as 10.5.

Trivia points:
The accepted translation from a hand-timed to an FAT time is to add .24 seconds
to the hand time to get your FAT equivalent. However, you cannot do that and
then call it “Fully Automatic Timed”. This is just a standard for
comparison sake. It remains a hand-timed time and remains in 10ths.

Filed under: Running,
Science & Running