1. Sanne I. de Vries, MSc; Ingrid Bakker, PhD; and Marijke Hopman-Rock, MA, MSc, PhD, are with the Department of Physical Activity and Health, TNO Quality of Life, Leiden, the Netherlands. Sanne I. de Vries, MSc; Ingrid Bakker, PhD; Willem van Mechelen, MD, PhD; and Marijke Hopman-Rock, MA, MSc, PhD, are with the Research Center of Physical Activity, Work, and Health, Body@Work, TNO-VU University Medical Center, Amsterdam, the Netherlands. Willem van Mechelen, MD, PhD, is with the Institute for Research in...