1. Child Development and Exercise Center, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, the Netherlands
2. Department of Epidemiology, Care and Public Health Research Institute, Maastricht University, Maastricht, the Netherlands
3. Sport and Exercise Medicine, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland; and
4. Department of Physiology, Institute of Biomedicine, School of Medicine, University of Eastern Finland, Kuopio Campus, Finland