Long runs are tough. They’re even tougher when you’re not exactly sure how long you’ve run. Tools like mapmyrun.com are nice, but the distance measurements aren’t always dead-on. With a three- or five-miler, a tenth of a mile deviation per mile isn’t such a huge deal. On a 15- or 20-miler, that can mean a difference of almost two miles. If you’ve ever embarked on a run this distance, you know how maddeningly unacceptable that is.
When I trained for my last marathon, I avoided this uncertainty by running the Jacksonville Marathon route for every long run. Think it’s boring running 20 miles straight all by yourself? Try doing it several times over. You truly start dreading every too-familiar street corner. The worst part: It was an out-and-back course. I’m getting the chills just thinking about it.
I decided there would be none of that this summer, when I start training for the Marine Corps Marathon in earnest.
The obvious fix is the Garmin, that brilliant mini-GPS the size of a regular watch that tracks your distance and pace.
My cheapo fix is the NikePlus, a neato little tool that hooks up to my beloved iPod Nano to track distance and pace. The NikePlus costs about $30, plus $5 for a little Velcro doo-dad to attach it to my shoe. Given my propensity for registering for expensive races, this a whole lot more realistic than a $300 Garmin Forerunner. But the NikePlus isn’t so accurate when you get it; even though I felt sluggish and nasty while running yesterday morning, it told me I was doing 7-minute miles. Thanks for the ego boost, but I’m pretty sure I didn’t just run my PR for a 5K on a slow run through my neighborhood.
So I headed to the track to try to calibrate it. I tried a neighborhood track just over the DC-Maryland line in Shepherd Park. Nice neighborhood, non-regulation track. Again, my plodding was charted as 7-minute miles, which would be ego-boosting if it weren’t so impossible.
Frustrated, I drove — yes, drove — to the track at Montgomery Blair High School, located a couple miles from my house. It was glorious. I was the only one there, and I think I nailed the calibration on my first 400-meter loop. I ran two half-mile repeats to test it, and each one came in at .5 miles, on the nose. And for the first time that day, since I was running half-mile repeats and not doing my standard neighborhood slog, the 7-minute miles were roughly correct.
I’ll withhold my final judgement until I test this on a longish run this weekend, but I think I’m in love.
Amy Reinink 
Hmmm….when you say “calibrate” does it actually have a calibrate setting or are you just trying to find out what the scale factor is for your own mental health?
Crap! I let the dork in me out.
Awww. Someone’s an enginerd! Good question, though — there’s literally a setting on the NikePlus that lets you calibrate the sensor. In layman’s terms, you basically tell the NikePlus: “No, fool, THIS is 400 meters. Remember this!” For whatever reason, the factory settings aren’t even close to being correct, but you can get it pretty close by going to a track and running a 400 to calibrate.