1. Children's Hospital of Eastern Ontario Research Institute; Ottawa; Ontario; Canada
2. Department of Pediatrics; CHU Ste-Justine and University of Montreal; Montreal; Quebec; Canada
3. Department of Kinesiology; University of Montreal; Montreal; Quebec; Canada
4. Department of Social and Preventive Medicine; Faculty of Medicine; University of Montreal; Montreal; Quebec; Canada
5. Division of Kinesiology; Department of Social and Preventive Medicine; Faculty of Medicine; Laval University; Quebec City; Quebec; Canada