I think yoga and pilates count as exercise. I think "doing an activity" includes meditating with an app other than grokker, shoveling snow, raking leaves, gardening, vigorous vacuuming, etc. -
but yoga and pilates definitely qualify in the "fitness"/exercise category! :)

Hi - I just noticed this week that Grokker finally added "doing yoga" as a new option among the "Self-Report" categories. Best wishes!