Validity of activity monitors in health and chronic disease: a systematic review oleh Van Remoortel Hans, Giavedoni Santiago, Raste Yogini, Burtin Chris, Louvaris Zafeiris, Gimeno-Santos Elena, Langer Daniel, Glendenning Alastair, Hopkinson Nicholas S, Vogiatzis Ioannis, Peterson Barry T, Wilson Frederick, Mann Bridget, Rabinovich Roberto, Puhan Milo A, Troosters Thierry