First off, can I just ask you not to take offence at the title of this post, as the idiot in question is me, not you. And that’s because the first couple of times I tried to calibrate my Nike+ unit I made a dreadful hash of it, through a combination of 1. Failure to read the instructions and 2. Spectacular ineptitude.
However, as a result of this, I ended up putting far more thought than was necessary into getting the calibration right, and as a result, seem to have gotten the accuracy of the unit virtually perfect.
I should probably admit that my early failings were caused by trying to calibrate the unit over a measured mile, rather than the 400m which is the recommended distance, as well as by inverting the ‘sender’ part of the unit when I strapped it to my running shoes. Naturally, it doesn’t say in the instruction that the unit won’t work if it’s upside down, as they assume that you will have at least a room temperature IQ in order to buy the unit in the first place, but trust me, it doesn’t work upside down.
Where I finally stopped myself from getting a place on the Darwin Awards nominations was when I finally realised two important things: 1. You need to measure 400m accurately in order to use that distance for your calibration run. And even more importantly, 2. You need to have already run at least a mile or so before you attempt your 400m calibration run.
That’s because, no matter how much I love mine, at the end of the day the Nike+ is just a glorified pedometer. So when you calibrate it over 400m (I used mapmyrun.com to find a suitable street that’s exactly 400m long) what you’re actually doing is telling it how many strides it takes you to run 400m. The unit then uses this as a hard, fast guide to how many strides you will take to run each 400m, whatever the distance you run. So, obviously, if you’re as fresh as a daisy, you’re going to be able to run 400m reasonably quickly, and crucially, taking fairly large strides, which gives the unit a completely false impression of your usual stride length.
Consequently, you’ll then go off to run a few miles, during which natural fatigue and thoughts of energy conservation will cause you to take shorter strides than on your calibration run, meaning that when you finish a run you know to be exactly 4 miles, and the Nike+iPod unit tells you that you’ve run 4.4 miles, you will decide that it’s rubbish and lose all faith in it.
However, calibrate the unit when you’ve run off a bit of your youthful exuberance, and your stride length will be much more typical of the stride length you average on training runs, and the accuracy will be greatly improved.
Frankly, I’m surprised that Nike themselves didn’t think to include this recommendation in their own instructions, as I’m pretty sure that it works. But maybe I just missed my vocation. Maybe, instead of writing ads and books, I should be wearing a white lab coat over at Nike in Oregon? Maybe someone, somewhere is going to give me an honorary Phd for this discovery. Remember, you heard it here first…