... instruments to measure physical activity may be questionable due to a lack of conceptual frameworks: a systematic reviewElena Gimeno-Santos1,2,3, Anja Frei4,5, Fabienne Dobbels6, Katja Rüdell7, ... of Washington; 2005.doi:10.1186/1477-7525-9-86Cite this article as: Gimeno-Santos et al.: Validity of instruments to measure physical activity may be questionable due to a lack of conceptual ... lungdisease, interstitial lung disease, asthma, emphysema,coronary disease, heart failure, elderly, physical activity, motor activity, activity of daily living, physical inactivity,Gimeno-Santos...