Occassional thoughts about orienteering

Saturday, September 14, 2002

More thoughts on route choice


Saving energy

The best route isn't necessarily the fastest time on a given leg. The best route is the route that gives you the fastest time for the course. Sometimes, you can give up a bit of time on a leg to save some energy that you'll be able to use later.

Take a look at the two routes on this map. Route A is the fastest route. Ten men ran both routes and the average for A is about 30 seconds faster than B. Seven women ran both routes and the average for A is about a minute faster than B. What is interesting is that the B route -- with a steep climb just before the control -- also slowed the runners on the next leg. The A route saved energy for later in the course.

Even if A had turned out to be slower than B, it might have been the best decision because it saved energy.

This example is from an academic paper on route choice by Rasmus Westergren in 1990. If you can read Swedish, it makes for interesting reading. The paper is available here.

Some ways to train route choice

I do a couple of things to train route choice:

1. I look at courses and pick routes. I try to find several alternatives even if one route looks obvious. I even look for alternatives that I think are not feasible. I'm not trying to see the best route, I'm trying to see the options. The idea is to make it easy to find the different options.*

2. I do a few route choice tests where I compare times on routes where one route looks to be clearly slower (perhaps running a trail that is far out of the way). I try to learn how much time I would lose by taking a crazy route. I run these tests with a heart rate monitor to try to keep the effort similar. Another way to do this sort of test is to run with someone -- each of you taking different routes -- either starting at the same time or starting a minute apart. I think it works best when you expect one of the routes to be clearly slower. It is interesting to see how much slower.

*Peter (I think) wrote something in a comment about the tendency for Swedes to miss routes that aren't straight because they are used to just going straight. In Sweden, the straight route is often the best. Compared to a lot of nations, Sweden is flat and the runnability doesn't vary much. Swede's get used to heading in the general direction without even looking for the alternatives.

posted by Michael | 10:32 AM


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