15 is not 9, but it might as well be. One cannot construct a distribution from 15 data points, therefore one cannot make statistical inferences. Even if one had sufficient sample size to realistically construct the distribution with reasonable significance, one could certainly not infer cause and effect from the correlation obtained!
We are in complete agreement here; correlation is not causality.
So Coyle's study amounts to an interesting story in which one can find basically anecdotal support for the efficacy of a bad pedal stroke -- if one were inclined to, say, try to start an argument on a message board.
Why do you presume the elite's stroke was "bad?" Because of a nonuniform force around the stroke? Coyle is not grading appearance; rather, he is measuring the forces applied throughout a rider's stroke. One can easily appear "smooth" and still have a force profile with a high, narrow peak. I suspect this is the case with elites.
Moreover, it says nothing about the effect developing a smoother stroke would have on an individual rider.
Which may in fact be detrimental, if by "smoother" you mean trying to apply a lower, more even force throughout the pedal stroke.
As for the rest, I don't have a MAP test from last year because I didn't have a power meter. And there would be serious problems with external variables because my training volume remained the same but my intensity this year went up a great deal, due to a fairly consistent racing schedule.
Power meters very well capture changes in both intensity and volume. It is important to have a baseline to understand if a particular approach is working (i.e., more HISS training, Powercranks) or just to increased workload.
I will do a test in the spring, which should be interesting because I expect to have less volume over the winter due to riding the PCs.
You may find that the reduced volume higher intensity approach effective (with or without PCs) and I certainly wish you the best success:!:
Certainly my experience is such and this again is where the baseline data would help proving. Next year I am going to save data from every ride (I put a Polar on my mountain bike) and even convert spin class HR data to an approximate TSS so every training mode is recorded to some degree.
I cannot point to a study that indicates a smooth stroke is preferable to a square one -- and even if I did, I'm sure I would find the same statistical issues with it that I do with Coyle's. If you can find a longitudinal study of an athlete who progressed from a smooth-pedaling weakling to a downstroke-exclusive powerhouse, I will buy you a beer (or send you a gift certificate to your beer store of choice). Same goes for the converse, ie. a strong rider who smoothed out his stroke and didn't improve.
Again, Coyle's study was not about appearance. Keep in mind too that even in the non-elite (less powerful group) 90% of the work performed is on the downstroke. I only wish a comprehensive longituinal study existed, and not for the free beer.