CatEye PW-TR100 Power Unit - Manual (Page 56)

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PW-TR100 : POWER UNIT
Reference Guide
Goal Setting
Training with power demands precise goal setting, which can help you be more efficient with your training.
Precise goal setting allows you to set a clear direction in which you want to move.
You should endeavour to set your goals in a specific manner. Don't set goals such as “be faster”.
Your goals need to be specific to you:
• Specific - e.g. take 1 minute off your personal best over 40-km, by increasing your power by 10 W
• Measurable - e.g. ride a 40-km TT in 58 minutes (rather than beat my regular training partner)
Example
Currently you can race a 40-km TT in 59:00 minutes. Average power output from the Cateye TR100 is
270 W. You want to complete a 40-km TT in 58:00 minute. Neglecting changes in position, and in
environmental conditions, there’s an almost cubic relationship (raised to the power of 3) between
power and velocity. You can then calculate your goal power based on your current average power.
Using the above figures and knowing that speed = distance / time, your goal power can be ascer-
tained. You must convert actual minutes to decimal (divide by 60)
Current speed = 40-km / (59 / 60) = 40.68 km/h
Goal speed = 40-km / (58 / 60) = 41.38 km/h
The percentage difference, or ratio, 41.38 / 40.68 = 1.017. Then multiply the ratio of the two speeds
(1.017) by itself three times = 1.017 x 1.017 x 1.017 = 1.052
Now multiply by current average power:
Goal power output = 270 x 1.052 = 284 W
NOTE:
This cubic relationship only works for flat or generally flat courses