Yesterday evening I took part in the Great City Race 5k around the streets of the City of London. I finished in just over 30 minutes, somewhere in the middle of the 6,000 people taking part. It's a corporate challenge where the proceeds go to the visually impaired so I was wearing a shirt with the logo of my little services company proudly displayed on it alongside those of mega-corps, big banks and insurance companies. Lots of fun and a great opportunity to relax both during the race and afterwards in the pub with some really hard working colleagues.
That's the review over. The most interesting thing was the data collected by my Garmin. In fact, two Garmins. Now, I ran the whole distance alongside a work mate and fellow C25K graduate who also happens to have exactly the same model of Garmin watch, the 610. The tall buildings of The City make it really difficult to get a good signal and at one point the route takes in a road tunnel that results in signal loss for about 15 seconds or so.
The result? Crossing the line together, one Garmin showed 4.86km and the other 5.23! Totally unreliable and of course trying to pace the run 'by the watch' was impossible. Looking at my route data after the run it appears as if I'm The Hulk after a night on the beer, wandering all over the place and crashing through buildings!
So, it's clear. When running in The City, your investment in your GPS watch may go up or down and past performance is not a reliable indicator of future results.......