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Monday, March 15, 2010

Power data from Froze Toes

Ok, this data is from the Froze Toes Race on 28Feb2010.  The sum of this data is:  273watt average, 300 normalized, 1096watt max, 2278 kJ in 2:19minutes for 62 miles.  There are a few problems with this data.  Primarily with the speed data.  My sensor stopped picking up very early (probably because the magnet on the spoke moved out of position).  The speed can be identified in the violet colored line.  Because the speed went out and I was not wearing my heartrate strap (I hate wearing it in races.  It does me no good and I don't like the sensation of wearing it when racing) my SRM data stops recording when I'm not pedaling (ie coasting).  The absense of zeros leads to higher averages.  Officially the race took 2:27 minutes (average speed 25.3mph) and my data says it took 2:19 minutes which indicates I coasted for about 8 minutes over the course of the race (if my calculations are correct). 

Additionally I want to point out that watt data is just slightly more tricky than one might guess.  Besides knowing the fact that the weight of the rider is important for understanding data (I currently weigh 160lbs @ 5'-11"), there are calibration factors to consider.  Had I not recently had SRM calibrate my SRM device, my wattages would be about 20 watts higher.  Because watt meters are temperature sensitive, I did zero my meter just before the race (which has an accuracy of 1-2%).   Also wattage numbers can be manipulated by adjusting the slope of the device or simply changing the data fields.  I think that is ridiculous to do, but I'm pointing out that it is easy to show monster numbers both accidently and purposefully. 

Have a great cycling day everyone and try to tear your cranks off! ;-)