Comparison of Rotational Traction of Athletic Footwear on Varying Playing Surfaces Using Different Normal Loads

As an athlete accelerates, stops, and changes direction, numerous forces are transmitted to the lower extremities. The interaction between an athlete’s shoe and the playing surface has been indicated as a factor in lower extremity injury risk. In particular, high rotational forces may result in increased injuries to the lower extremities. Rotational traction forces produced by eight different cleated shoes on Kentucky bluegrass (Poa pratensis L.), AstroTurf GameDay Grass 3D, FieldTurf Revolution, and Sportexe Omnigrass 51 under three normal loads (vertical forces) of 787, 1054, and 1321 N were measured using Pennfoot, a portable traction testing device. Of the treatments in this study, shoe type influenced rotational traction most, with differences among shoes being nearly four times as large as those among playing surfaces. Traction was either the same or within several Nm on each surface tested. Traction on the three synthetic turf surfaces ranged from 49.3 to 53.1 Nm and the traction level of Kentucky bluegrass was 52.3 Nm. Traction levels among shoes ranged from 43.8 to 58.6 Nm. The results of this study indicate that footwear selection has a larger effect on rotational traction, and potentially injury risk, than the playing surfaces evaluated in this study. Traction Testing on Natural and Synthetic Turf The interaction between an athlete’s shoe and the playing surface likely influences lower extremity injury risk. Specifically, injuries to lower extremities may result from an athlete’s foot becoming “entrapped” in the playing surface during pivoting movements (Lambson et al, 1996; Orchard et al., 2001; Torg et al., 1974). Researchers have attempted to quantify lower extremity injury risk by measuring the rotational traction forces that occur between shoes and playing surfaces (Andreasson et al., 1986; Bonstingl et al, 1975; Heidt et al., 1996; Livesay et al., 2006; McNitt et al., 2004a; Torg et al., 1996; Villwock et al., 2009a, 2009b). Rotational traction is the traction related to rotational motion about an axis normal to the surface (American Society for Testing and Materials, 2009). In the following studies, Published in Applied Turfgrass Science DOI 10.2134/ATS-2013-0073-RS © 2014 American Society of Agronomy and Crop Science Society of America 5585 Guilford Rd., Madison, WI 53711 All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. T.J. Serensits and A.S. McNitt, Dep. of Plant Science, The Pennsylvania State Univ., 116 ASI Building, University Park, PA 16802. Received 25 Oct. 2013. *Corresponding author (serensits@psu.edu). Published July 9, 2014