Today introduced another increase in interval time for the functional threshold power (FTP) intervals, from 12 minutes to 15 minutes. This is used to build my FTP by continually increasing the training load at FTP so that I hopefully improve my power. It also incrementally gets me used to training hard at longer and longer intervals. This should be helpful when I get to the next phase of training that aims to really lift FTP by implementing intervals at power levels above FTP.
Something I've noticed as I've been going along is that my Ergomo has somewhat higher power readings in the first interval, while displaying somewhat lower power readings in subsequent intervals. For example, if you look at the graph and the Training Summary below, you'll see that my first FTP interval has a normalized power (Norm Power) of about 264 watts, while the second FTP interval has a normalized power of 258 watts.
Typically, I wouldn't think much of the difference, but I'm riding these workouts on a Computrainer in Erg mode, which holds the load constant, and should result in near identical normalized power readings across the intervals. In fact, looking at the Computrainer's workout data shows idnetical normalized power readings across both intervals.
My hinch is that this is an exhibition of the Ergomo's fatal flaw. It only reads power from one leg, and then doubles it, assuming you have balanced leg strength. I suspect that perhaps I favor my left leg early in the workout, and my right leg as I get tired. This would result in higher readings for the early intervals and lower readings for the later intervals.
Workout Summary
Entire workout (205 watts):
Duration: 1:00:00
Work: 738 kJ
TSS: 76.7 (intensity factor 0.876)
Norm Power: 228
VI: 1.11
FTP Interval #1 (264 watts):
Duration: 14:58
Work: 237 kJ
TSS: 25.7 (intensity factor 1.016)
Norm Power: 264
VI: 1
FTP Interval #2 (258 watts):
Duration: 14:59
Work: 232 kJ
TSS: 24.6 (intensity factor 0.992)
Norm Power: 258
VI: 1
