Have a look at a Chrome extension called Painsled. It's free, and the best I've come across for recording all erg data (inc. HR if linked up). You can export everything as a single TCX file.
Mark - I know this may be a little out of the bounds of what GC is aimed at, but is there any chance a dev build could use this data to map an average of force curves? I have written a few VBA scripts that do this in excel, but it's a bit of a pain to use as my excel skills are too limited to make it fully automated, and it'd be nice to have all the data in GC.
Thanks,
Callum