BYOP88 said:
Saw this on twitter and found it interesting, can anyone one answer it:
"What's the point in monitoring one Colombian rider for a few weeks? That's not a proper study on altitude natives, is it?"
When you are trying to determine something, via a study, you are looking at extrapolating data from a small subset of data points from a larger population.
Sky's hypothesis: Henao's strange blood paramters are due to him being an "altitude native" Colombian training at altitude in Colombia over Winter.
Brailsford said the team was also commissioning independent scientific research into the effects of prolonged periods at altitude on those returning from sea level, with specific reference to "altitude natives".
When it comes to hematological parameters, there are differences between riders, and differences within riders over a racing season (off vs on and start vs end of season). There are also differences between seasons (summer, winter, etc). Further, there are differences between early morning and evening readings, thanks to diurnal rhythms, etc, as well as "at altitude" and "at sea level".
It would be exorbitantly expensive to monitor a large number of athletes all year, so statistical methods seek to hone in on the pertinent variables through a large enough sample size (data points).
A nice sample size that allowed comfortable extrapolation could be (for eg) 30 riders being tracked for 12 weeks, tested twice a day. This gives us 30 x 12 x 7 x 2 (daily samples) = 5040 data points / 30 riders.
What Sky are doing is one rider, for 8 weeks. No information (for a change) is being provided regarding the testing protocol, but I would hazard a guess that it's daily testing. So 1 x 8 x 7 = 56 data points / 1 rider.
The biggest variable (between riders) however, has a sample size of 1. It's impossible to extrapolate from that one rider to other riders. This single sample is not useful for proving that Henao's anomalies (the thing trying to be explained) are in fact specific to Colombian natives Wintering in Colombia, or still specific to Henao himself (and any potential doping protocol).