The Effect of Heel Studs on Retraction Kinematics of the Equine Hind-limb during Canter on Grass

Introduction: Screw-in heel studs are used throughout the equestrian industry with the purpose of enhancing hoof-ground interaction to optimise performance (Harvey et al., 2012). Limited research is available regarding stud use and their effect on equine limb kinematics; however, suppositions can be made in relation to our knowledge of the effect of cleated footwear on human athlete limb kinematics throughout sport (Fulco et al., 2000). The aim of this study was to assess whether the use of heel studs effected the kinematics of the equine hind-limb, during the phase of retraction, whilst cantering on grass. Method & Materials: External skin markers were positioned at the tuber coxae, cranial point of the greater trochanter and the lateral epicondyle of the femur, the distal end of the tibia at the lateral malleolus, distal end of the metatarsus and three markers on the lateral hoof wall forming a triangle on four event horses, ranging from Novice to Advanced Level. All horses cantered within a 30 meters standardised field-testing environment. This was done three times with the use of studs followed by three times without the use of studs for each horse. All measurements were taken on the same day to prevent anomalies within the results. Video footage was obtained using a high-speed motion camera (Iphone 6S Plus/ 240 frames per second) for analysis using Version 7 Dartfish Pro. Using IBM SPSS 25 Statistical Software a Paired Samples t-test was used to determine the significance level between the different joint angles of the hind-limb with and without the use of studs. Results: Results showed use of studs significantly alters the kinematics of the equine hind-limb Discussion & Conclusion: This study only begins to answer the question into the overall effect of studs on a competition horse’s limb kinematics. Results of this study indicate, that the alterations of the joint angles of the hind-limb are the consequence of studs decreasing stride length and improving traction between the hoof and ground surface (Harvey et al., 2012). Therefore, causing a jarring effect within the limb at the point of landing with the ground surface Kane et al., 1996; Hill et al., 2001). This suggests that studs have the potential to alter the ground reaction forces (GRF) and loading forces experienced within the limb (Gehring et al., 2007). As such, there is a need for further investigation in to how stud configuration, stud size and how fore and hind-limb studs interact on the horse’s kinematics; in order to understand the true effect of the repetitive usage of studs and the long-term potential injury risks associated.