Since its construction was completed in 2012, JDL Fast Track has set about living up to its name by hosting some of the top performances in the southeast. But how fast is it really? How does it compare to our state's more historic indoor track? The Dick Taylor Track in Eddie Smith Field House, on the campus of UNC Chapel Hill, opened in 2001 - but many of the state's "old timers" (including me) can remember the old wooden track in the "tin can" building that used to sit on the same spot. UNC's indoor track has hosted nearly every NCHSAA state championship, with the exception of the last two that were at JDL (and one that was outdoors when UNC was unavailable).
My project over the next couple of weeks is to answer the question: which track is faster? It will take some time to gather and analyze the data,
What does "flat 200" mean?
The standard length of an indoor track is 200 meters (although there are still some 160-meter tracks out there, and some places have "oversized" tracks). However, some tracks are perfectly flat all the way around, while others have banked curves - the track is progressively raised, like they use in many auto racing tracks. Here's an example of a banked track, at Virginia Tech:
Why are banked tracks considered to be faster than flat tracks?
First, a little basic physics. When you run, you use energy to do work (yes, that's the scientific term as well as the common term). You do work to move yourself forward, but you also do work whenever you have to change direction. So, whenever you're turning (going through a curve), you have to do MORE work to maintain the same speed - forward work and turning work combined. If you're running at top speed, though, like in the 300, you can't do more work - so you have to slow down. (You have no choice, the laws of physics dictate this.)
There, that wasn't so bad, was it? Now here's the simple truth about indoor tracks:
- They have MORE curves than outdoor tracks (twice as many)
- The curves are tighter, forcing you to do more turning work.
As a result, it takes more work to maintain speed on an indoor track than it does on an outdoor track. In distance races, this leads to earlier fatigue; in sprint races, it prevents you from reaching the top speed you could achieve on an outdoor track.
A banked track helps you by changing the angle at which you apply force. In simpler terms, the track does some of the turning work for you, which allows you to keep more of your effort focused on maintaining forward speed. Banked tracks "steal" a little less energy from distance runners, but the big effect is in the sprints - banked tracks allow for higher top speeds in the curves of the 300 and 500, and especially the 4x200.
Does that mean indoor tracks are slower than outdoor tracks?
YES. Absolutely and unquestionably, physics says indoor tracks are more difficult for any race that has at least one curve. How much does it affect a runner? Well, that's harder to answer, because it depends on the particular characteristics of the track you're talking about.
What makes a "flat 200" track faster or slower?
One thing that affects the speed of ANY track is the surface. Both UNC and JDL have Mondo surfaces, made by the same company that surfaced the tracks for the last three Olympics. UNC's Mondo surface is, obviously, much older, and the company says that their newer surface is superior, so the advantage there goes to JDL, albeit only slightly. This is the only factor that affects the speed of a straight race like a 55 or a 60.
The other factor that affects the speed of the track is the radius of the curve (how "tight" the curve is). The tighter the curve, the more of your work goes into changing direction, and the harder it is to maintain your speed. This has two different effects, depending on the distance you run: for shorter races it limits your top speed, and for longer races it steals energy.
How do UNC and JDL compare in terms of surface and curves?
The curves at Dick Taylor Track have a larger radius (in common terms, they are wider), which results in shorter straightaways. This makes it a little easier to maintain speed in the curve, and in theory that benefits sprinters in the 300 and 500. The benefit woud probably be less for distance runners, because they aren't trying to maintain top speed through the curve (so for them, the number of curves is more important than the radius). Is that enough to overcome JDL's newer and faster surface? We'll TRY to find that our with some hard data over the next few weeks.