Explain additional statistics

[Gregory Smith]

On the statistics page, there are three parameters under the heading "other stats".

rPower Heart Rate drift rScore

Could you include an explanation of what each of these are and how they are calculated, either in a mouse over pop up, or as a link from the parameter name.

I ask because, even though I was the person who asked you to include HR drift, I don't remember the measurement points for it.