.gov is the current domain extension type used by most United States government or government supported sources. You can trust these sources to be, if not accurate, then at least backed by the majority of the US population and governing power as the most commonly perceived knowledge in that sector.
Well,if your health is bad it well mess you up in the future and you won't be able to do anything any more
Since training and stretching for flexibility is a physical activity, I would say yes you should record it.
