Diminishing returns

Last night I set off to do the ‘Hour of Power’ workout, where you’re supposed to pedal at a constant rate, the highest level you can maintain for an hour.  This is approximately your FTP (Functional Threshold Power).  I did a test ride on TrainerRoad last week to measure FTP and it came out at 257 watts (based on my turbo trainer’s power curve).  Actually the HoP is intended to be ridden at 101% of FTP, presumably meaning that you shouldn’t actually be able to maintain that, unless your fitness has improved.  So I created a custom workout in TrainerRoad with a 2 minute initial low power interval, followed by a 60 minute solid interval, scaled to 101% of FTP (which at the moment equates to 260 watts).  I always warm up first for 10 minutes, then calibrate the Tacx.  I do this before starting the TrainerRoad workout, which is why it does not show in the trace.  The initial two minute block is just for acclimatisation.

The data upload to TrainerRoad is here, and below is a screenshot showing the sorry affair:

Screen shot 2013-02-15 at 21.37.08

You can probably tell from the image that it was a game of two halves.  For the first half I was able to keep the power slightly above the target, but then around halfway it started to drop and never recovered.  The sharp downward spike occurred when I had the bright idea that maybe I’d run out of energy.  So I got off the bike and went and had a gel.  It had no effect.

So what caused the decline?  Two possibilities occur:

  • I didn’t have enough energy, and the gel could not take effect quickly enough
  • I hadn’t paced myself properly

I had been careful in the few hours beforehand and eaten a good few hundred calories.  So I’m going to discount lack of energy as the chief reason.  If you look closely at the yellow power line, when all was well I was generally slightly above the target blue block.  The target blue block was already 101% of what I should be capable of maintaining, and yet I was merrily riding at a higher intensity than that.  Probably an average of 265 watts during the first half.  Last week I completed an hour at 253 watts, and then later did an FTP test that came out at 257.  Who was I trying to kid, thinking I could then go and push 265?

Lesson learned, I think.

The second half was a fairly grim experience.  Now it’s just a wiggly yellow line on a graph, but there is pain embedded in those wiggles.  I seriously considered abandoning it, several times.  I would try and push it back up to target, and then fall away almost immediately.  At the time it’s very disheartening, because it feels like failure.  In the cold light of day I can see that it probably did me good.  Despite the diminished power in the latter stages, I will be fitter in the next few days than I would have been if I hadn’t trained, or if I had abandoned early.  And I still averaged 251 watts in the 60 minute interval.

Tomorrow I am hoping to take the bike out for some tests for the first time.  Maybe ride the local 10 course and see what my current pace is.

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Posted on February 15, 2013, in Training. Bookmark the permalink. Leave a comment.

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