1 Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, AB T2N 1N4, Canada; Alberta Children's Hospital Research Institute, University of Calgary, AB T2N 1N4, Canada; Hotchkiss Brain Institute, University of Calgary, AB T2N 1N4, Canada; O'Brien Institute for Public Health, University of Calgary, AB T2N 1N4, Canada; Department of Pediatrics and Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, AB T2N 1N4, Canada. Electronic address: caemery@ucalgary.ca.
2 Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, AB T2N 1N4, Canada; Cardiovascular Concussion Research Laboratory, Faculty of Kinesiology, University of Calgary, AB T2N 1N4, Canada; Alberta Children's Hospital Research Institute, University of Calgary, AB T2N 1N4, Canada; Hotchkiss Brain Institute, University of Calgary, AB T2N 1N4, Canada; Libin Cardiovascular Institute, University of Calgary, AB T2N 1N4, Canada.