Kinematic Analysis of the Collected and Extended Jog and Lope of the Stock Breed Western Pleasure Horse by Joanna Elizabeth Shroyer A dissertation submitted to the Graduate Faculty of Auburn University in partial fulfillment of the requirements for the Degree of Doctor of Philosophy Auburn, Alabama December 13, 2010 Keywords: kinematics, stock breed western pleasure, jog, lope Copyright 2010 by Joanna Elizabeth Shroyer Approved by Wendi H. Weimar, Chair, Associate Professor of Kinesiology Robert Gillette, Director of Animal Health and Performance Program David D. Pascoe, Professor of Kinesiology Elizabeth L. Wagner, Assistant Professor of Animal Sciences Abstract Scientific research concerning stock breed western pleasure horses is limited. Therefore the purposes of this investigation were to determine if stock breed western pleasure horses 1) alter stride length independently of stride duration for the collected and extended jog and lope; 2) perform the extended jog and lope as a gait that more closely follows guidelines set forth by major stock breed associations for western pleasure competition than does the collected jog and lope; 3) maintain a more correct head and topline carriage during the extended jog and lope than during the collected jog and lope, and 4) perform the extended jog and lope with a more natural way of going thereby reducing risk of joint injury and trauma compared to the collected jog and lope. Reflective markers were placed over seven points on the lateral side of the left and right fore and hindlimbs as well as the medial aspect of the coffin bone; additional markers tracked the temporal bone and vertebral column. Three successful strides of each gait were analyzed using the Peak Motus© 1994‐2004 motion analysis system (Peak Performance Technologies, Inc., Englewood, ii Colorado, USA). Digitization, transformation, smoothing, and normalization techniques followed standard kinematic techniques. Results indicate that all gaits were performed as four‐beat stepping gaits with diagonal couplets and a lateral footfall sequence with the exception of the right lead collected lope, which exhibited a diagonal footfall sequence. Stock breed western pleasure horses do not alter stride length independently of stride duration during the jog or the lope. Further, the extended jog more closely followed the guidelines set forth by major stock breed associations for western pleasure competition than did the collected jog, however the extended lope did not more closely follow guidelines than did the collected lope. Horses’ head carriage and topline did not more closely follow gait performance guidelines during the extended jog or lope as horses maintained a level topline during both the extended and collected jog but did not maintain a level topline during the collected or extended lope. It was concluded that continuing gait definition transformations by more accurately describing the jog and lope as four‐beat stepping gaits without visible separation of the diagonal pairs and to encourage even greater forward motion than was seen in the present study should theoretically reduce joint injury and trauma to the stock breed western pleasure horse while maintaining proper performance of the gaits. iii Dedication I would like to dedicate this work to “Nick” who has continued his dam’s influence in my life and allows me first hand knowledge of the stock breed performance industry. “Nick” represents all stock breed western pleasure horses, as they are truly the most misunderstood and misjudged athletes of the equine industry. To your trainers, breeders, keepers, riders, and owners who cannot possibly understand the depth of your heart and commitment to their own self edification through recognition and blue ribbons, I offer this slight glimpse into your little understood way of going. iv Acknowledgments The author expresses her sincere gratitude to numerous people for their part in the development of this dissertation. A multitude of thanks is due to Dr. Wendi Weimar for providing direction, mentorship, expertise, and friendship throughout my doctoral program. Appreciation is also due to the other members of my dissertation committee Dr. Robert Gillette, Dr. David Pascoe, and Dr. Betsy Wagner for their guidance and support throughout this project as well as to Dr. Cindy McCall for graciously agreeing to serve as the outside reader. Data collection would not have been possible without the help of my research team including Dr. Wendi Weimar, Dr. Betsy Wagner, Dr. Robert Gillette, Dr. Justin Shroyer, Dr. Josh Bruce, Ande Sumner, Ashley Bruce, Casey Gates, and Oluremi Onifade; your help was indispensable and greatly appreciated. Further thanks are extended to Steve Tidwell and Kimberly Tidwell of Tidwell Training Center, Summer Salter of Summer Salter Show Horses, and Kyle Grant of Kyle Grant Show Horses in Tallassee, Alabama for access to the horses used in this project. Their dedication to improvements in training and showing of western pleasure performance horses is unequalled. Credit is also due to the Auburn University v Veterinary Sports Medicine program including Sherry Johnston and Dr. Craig Angle for allowing me access to and teaching me how to make use of the movement analysis software utilized in this project. I must also thank Dr. Nels Madsen from the Department of Mechanical Engineering for his input and assistance with mathematical processes that were vital to the completion of this work. Continued thanks are extended to my parents, Richard and Beth Booker, for their unending support of my equine passion and confidence in my success; I would not be where I am today without you. To my husband, Justin Shroyer, thank you is not enough for your love and support throughout this process. Finally, I would like to thank my Lord and Savior, Jesus Christ, for honoring His promise in Psalm 46 to be my refuge and my strength. vi Table of Contents Abstract.............................................................................................................................. ii Dedication ........................................................................................................................ iv Acknowledgments .......................................................................................................... v List of Tables..................................................................................................................... x List of Figures ................................................................................................................ xvi List of Abbreviations ..................................................................................................xxvi Introduction .....................................................................................................................1 Stock Breed Horses .............................................................................................1 Western Pleasure .................................................................................................3 Statement of the Problem...................................................................................11 Purpose of the Study ..........................................................................................14 Hypotheses...........................................................................................................16 Operational Definitions......................................................................................16 Literature Review ..........................................................................................................26 Defining Gaits Through Kinematics ................................................................27 Head Carriage......................................................................................................58 vii Injuries ..................................................................................................................61 Summary ..............................................................................................................63 Materials and Methods ................................................................................................65 Animals.................................................................................................................66 Recording Techniques........................................................................................68 Data Collection ....................................................................................................71 Data Analysis.......................................................................................................72 Statistics................................................................................................................76 Results .............................................................................................................................79 Collected Jog ........................................................................................................80 Extended Jog........................................................................................................87 Collected versus Extended Jog..........................................................................93 Collected Lope.....................................................................................................98 Extended Lope...................................................................................................121 Collected