## 17.8.16

### DOES ANYONE REALLY RUN 400 METERS?

During some breaks in the Steel Mill Modellers gathering, I was watching coverage of the Olympics, er, let's be formal, the Games of the XXI Olympiad, and there were some real track events going on, including the sprints.  That got me to thinking: to fit the 400 meter dash (the successor to the Twenty Chains Sprint) onto a curved track and provide a common finish line, the start lines are different lane-by-lane with the person who drew the inside lane starting somewhere along the end of the stretch and the person on the outside lane up in a curve.  Makes sense.  Then came the overthinking, always a dangerous thing: as the circular constant, π, is transcendental, whilst 400 meters as a straight line distance is a natural number, you have at best an approximation to 400 meters in each lane, and the runner who stays as close as is legal to the inner lane stripe all the way around travels a shorter distance than a runner who would stay closer to the outer lane stripe (which itself might be a speed-enhancing strategy in the outside lanes, think about it.)

Relax.  The margin of error is probably small enough as to not fret about it.  But there is a margin of error, and Dave "Voluntary Xchange" Tufte researched it in the use of timers in swimming.
[I]n swimming there are a lot of ties.

How is it possible that there are ties when we can measure time accurately to 3 to 6 digits?

Here’s why: because in 0.001 seconds a swimmer travels about 2 millimeters, but the construction tolerance for differences in pool lane lengths is plus or minus 30 millimeters (due to expansion and contraction from heat and cold).

FINA (which governs international swimming) recognized 40 years ago that improvements in timekeeping simply is not differentiating swimmers better.
There's a more intriguing recent rule change in swimming.  In the past few Olympics, I've noticed racers coming off the blocks or the turns and making like an eel rather than surfacing and starting to flail immediately.  And there are apparently rules governing the eeling zone (dear reader, if you know the technical terms and the rule references, please advise) that include designating it with different colors on the lane dividers (yet another margin of error?)  And it appears that the eeling zones are different for sprints than they are for the distance races, e.g. the 1500 meters.  Or is it as simple as, at the margin, a small advantage from staying submerged matters more in the shorter races?

Dave Tufte said...

How much do you want to know about "eeling". My son is a senior (high school) swimmer, so he knows the rules.

The little I know is that "eeling" is limited because most competitive swimmers can do it quite effectively from end to end of the pool.

Dave Tufte said...

He says it is not called "eeling" it is called "streamlining", and the underwater kick is called a dolphin kick.

I was wrong. They can't streamline underwater for 50m. The limit is 15m. That is largely because Ryan Lochte could do it so much better and longer than everyone else.

Each stroke has different requirements for what motions are allowed in the streamlining.

In some events, some racers may surface earlier because they are faster on the surface than underneath.

He says there is no difference in the 15m limit for each lane. So it could be a camera illusion. Alternatively, in swimming the faster racers get the middle lanes, and they tend to do better streamlining, so they may go further than others.

Stephen Karlson said...

Streamlining is for trains, but OK, let me add an entry in the Thesaurus ...

Perhaps, as it is adapted from the dolphin kick, which is part of the butterfly repertoire (such a wasteful stroke, despite some genius inventing it to get the recovery motion out of the water) and as such more likely to be used by the sprinters than by the distance guys, who, unless I've missed something, only use the free in their events.

Thus it makes sense for the distance guys to get back to their normal motion and pace immediately off the wall.