Curvaceousness ain't always a plus.

One of the inspiring features of the Louisiana Marathon route is the winding path taken around the LSU Lakes. It's simply beautiful. So idyllic, so tranquil. An eye-fest of nature's grandeur (notwithstanding the fact that the LSU Lakes are actually manmade). In fact, the entire marathon route can legitimately be called stunning. Based on reviews from runners touting scenic value, the Louisiana Marathon route is considered one of the top routes in the country, and surely those winding, curving scenic views help give it that reputation. But then there's the dark side.

A curving route begs several questions: do I run down the middle of the road, or do I hug the outside or the inside; indeed, how should I actually run through all those twists and turns? As it turns out, you can do most any of those things (unless specifically marked on the course otherwise), but if you run the route differently than it was certified, you will undoubtedly be running a longer race than planned.

Measuring two consecutive right turns
(Figure from the USATF Course Measurement and Certification Procedures Manual) 

This first figure is a simple example of how USA Track and Field instructs its certifying agents to measure a portion of the route distance. Here, two right turns in succession will be executed by runners. The certifying agent will measure the shortest possible route by pedaling a bicycle equipped with a Jones Course Measuring Device, typically about a foot from the curb.

A curvy portion of the LSU Lakes
(From Bing Map in Garmin Connect)

Traveling any other route than this shortest one will result in a longer distance traveled and ultimately in a slower finish. This gets a bit trickier when we consider winding curving route portions like those alongside the LSU Lakes (see figure at right). Here, the guidance to certifying agents is to take the straight line route, insofar as possible. This results in weaving back and forth with respect to the roadside, but straight as the crow flies. The figure below shows one possible example. One might think that there's only a small difference between running this measured path and running one a little farther out.

Measuring a winding section of a course route
(Figure from the USATF Course Measurement and Certification Procedures Manual) 

Sure, if we only count one turn, the difference will not be large, perhaps only a matter of feet. Make numerous turns in a long, long race like a marathon and the difference in distance adds up. I'll give two demonstrations that illustrate this point.

My Usual Walking Route

The timelapserunner's usual route for the cross-training walks is roughly three miles. Well, that depends actually. If I go left from the front of my house, I walk on the left side of the street, against traffic (to see the cars that might hit me). Since this route is a closed loop, making this choice results in a walk that's closest to the shortest path, as it is up against the inner curb. Distance traveled this past Monday walking this path: 2.97 miles. If I go right from the front of my house, I again walk on the left side of the street, against traffic, but this time I'm taking the longest path around the neighborhood by walking that outer edge of the route. Distance traveled yesterday, using the outer path: 3.11 miles. The difference is a whopping 4.7% of the mean distance traveled!

The Louisiana Marathon Route

I used the Garmin Connect course mapping feature to trace out the Louisiana Marathon route from start to finish. The distance provided by that feature was 26.79 miles. That's 0.57 miles (or 2.2%) LONGER than marathon distance! Presumably the distances provided by that feature were NOT computed by taking advantage of running the shortest possible distance at all times, resulting in a longer total route distance.

The bottom line is this: run the shortest distance possible on race day or face the possibility of having to run (as much as) an extra 0.6 miles to get to the finish - that's probably an additional 7 minutes of additional running - and elapsed time. Something to think about, for sure.

TODAY'S WORKOUT: A nominal four miles around the lakes at an average pace of 11:52 per mile (planned for 11:48), using run/walk intervals of 2:03/1:00, with the run pace nominally at 10:28 per mile. No muscle or other problems to report.