I've only noticed this on the activities page recently - can anyone tell me what it is & how it gets populated - I have a 705 if that's relevant,
thanks
There are lots of articles on training effect. Suggest you do a simple google search and you will find plenty of information. The bottom line is that it is an attempt to quantify how beneficial a training session is.
However, as GERRYCAN noted, it is not calculated for the 705.