Friday, September 12, 2008

garmin footpod...working properly?

after running outside on 31 August, the humidity came back.  i put the footpod back on my shoe and hit the treadmill on tuesday.  amazingly, my 5 mile treadmill run registered as exactly 5 miles on the footpod.  after having errors of up to 15%, i thought this was an anomaly.  so, i decided to apply the scientific method, and test a couple of variables to see if i could isolate the problem.  this was a steady 5 mile run at a comfortable pace, with no variations of pace.  on the next day, i decided to see if speed was the issue.  i used the treadmill as my constant, running on the same treadmill as tuesday.  i started out the run at the same pace as the day prior, and kicked up the pace from 8:34/mile to 6:49/mile for 2 x 1-mile intervals.  the 405 was reading the same pace as the treadmill for the first 1.5miles, then i kicked up the pace...for the entire run, the 405 read +/- .01-.02 of what the treadmill displayed, and by the end the difference was negligible.  so, variable speed was not the issue.  on friday, i decided to use another treadmill.  did a steady 4 miles on this day, with a few variations of speed in the last mile.  again, the readings were near the same.  on sunday, i tried yet another treadmill, this time for 10miles...on this day, the garmin read .05 miles ahead of the treadmill...that's an error of .5%...not bad.  to top it off, for the first time, the 405 gave a reading faster than the treadmill.  so far, i've had 6 accurate treadmill runs in a row.  today, the humidity dropped, and it was nice this morning.  i took off the footpod for an outdoor run.  i may have jinxed the footpod by removing it from my shoe. 
i've attached a graph for jon...this was one of the successful indoor runs. 

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