1. School of Therapeutic Sciences, Centre for Exercise Science and Sports Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Johannesburg, South Africa.
2. Department of Chemical Pathology, National Health Laboratory Service, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Johannesburg, South Africa.
3. Department of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Johannesburg, South Africa.