Feeling chippy?

After P.A.M.’s run I was thinking about chips. In this race two people finished in ~38:08 seconds. One was a woman, and one was I. According to Paul’s chip mat she finished at 38:08.2 and I finished at 38:08.3.

I remember her being a few inches ahead of me, so I’m not doubting the order, but it made me think.

In the old days you finished (in theory) when your chest crossed the line. Now we finish when the foot with the chip on it crosses the line. My stride is probably about 5 feet (give or take) which is roughly 1/1000th of a mile (give or take). I was running (again give or take) 6:08 minute miles. So it takes me about 368/1000 seconds to run a stride.  The foot with the chip might be anywhere from .18 seconds behind to .18 seconds ahead of my chest.

If two people are running side by side the error of measurement is doubled .36 seconds. That’s a lot. That’s more than I lost by.

Someone running 8 minute miles has an error that is roughly half a second.

John B. was talking to me about a race he’d run where each runner had two chips, one on each foot, and the finishing time was the average of the two. That seems like a good approach, the average will probably not be exactly where the chest crosses, but at least it provides a number which is consistent for everyone.

At first I thought, “Oh that’s silly, you don’t need that much accuracy.” And then I realized. Oh yes, you might, in fact I did need that much accuracy — in my last race.

Again — I do think the order was correct. But it might not have been.

Paul, Wally, John, I want two chips!


One Response to “Feeling chippy?”

  1. jk Says:

    If race directors follow the rules, it’s (a) gun time, not chip time, that counts, and (b) chest across the line determines finishing order, not chip time. It’s actually worse, though, than you think — at full end-of-10K stride in my Glamorous Youth it was ~100 stride-pairs per 400 meters — or 13′ per stride pair. That’s enough, if the location of the foot-plant is right, to go entirely by the mat without touching it with the chip-foot. No chip time at all.

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