1 National Research Centre for the Working Environment, 2100 Copenhagen, Denmark ; Physical Activity and Human Performance group, SMI, Department of Health Science and Technology, Aalborg University, 9220 Aalborg, Denmark.
2 National Institute for Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven, Netherlands ; VU University Medical Center, 1081 BT Amsterdam, Netherlands.
3 University of Massachusetts Lowell, Lowell, MA 01854, USA.
4 Work Research Centre, Dublin, Ireland.
5 Department of Psychology, Lund University, Box 213, 221 00 Lund, Sweden.
6 Netherlands Organisation for Applied Scientific Research (TNO), Delft, Netherlands.