1 Title: Running quietly reduces ground reaction force and vertical loading rate and alters foot strike technique. Authors: Xuan Phan 1,2 , Tiffany L. Grisbrook 1 , Kevin Wernli 1,3 , Sarah M. Stearne 1 , Paul Davey 1 and Leo Ng 1 Affiliations: 1 School of Physiotherapy and Exercise Science, Curtin University, Perth, WA, Australia 2 Homecare Physiotherapy, Lifecare, Perth, WA, Australia 3 Ferry Road Physio and Functional Therapies, Southport, Qld, Australia Address correspondence to: Dr Leo Ng School of Physiotherapy and Exercise Science Curtin University GPO Box U1987 Perth, WA 6845 Email: Leo.ng@curtin.edu.au Phone: +61 8 92661001 Fax: +61 8 9266 3699 Acknowledgements: The authors would like to thank the participants who dedicated their time to participate in this study. Dr Roger Collinson and Dr Jenny Lalor require acknowledging for their assistance. Finally, we would like to acknowledge the guidance and support provided by the late Professor Di Hopper, her passion for research will be missed. Funding and grant bodies: The authors declare that no funding or grants were received to conduct this study. 1