Kinematic Analysis During Straight Line Free Swimming in Horses: Part 1 - Forelimbs

Abstract

Background: Swimming is used for rehabilitation and conditioning purposes in equine sports medicine despite the lack of understanding of equine swimming kinematics. The aim of this study was to assess forelimb joints kinematics (elbow, carpus, and fetlock) in swimming horses. The specific objectives were 1- to calculate and compare joint angles in swimming vs. passive mobilizations (PM), 2- to determine joint angular velocities during a swimming stride cycle.Methods: Eleven elite endurance horses swam in a 100-m straight pool. Underwater (swimming) and overground (PM) videos were recorded from the horses' left side. Joint markers were applied on the lateral hoof wall, lateral metacarpal epicondyle, ulnar carpal bone, lateral humeral epicondyle, and the greater tubercle of humerus, from which elbow, carpus and fetlock angles, and angular velocities were obtained. As a reference, maximal fetlock, carpus, and elbow flexion/extension angles were determined during PM overground. Differences between angle extrema, angular velocities and range of motion (ROM) were compared.Results: Carpus and fetlock ROM were significantly smaller (p < 0.001) during swimming when compared with PM, while there was no difference in elbow ROM between both situations. The carpus had the greatest ROM of all joints during swimming. Absolute angular velocities values of all joints during swimming were greater during retraction than protraction (p < 0.001). When compared to other joints during protraction, the carpus joint reached the highest angular velocity.Conclusion: Swimming, as a rehabilitation exercise, has the potential to benefit horses where great elbow ROM with a moderate carpus and fetlock extension are wanted.

Kinematic Analysis During Straight Line Free Swimming in Horses: Part 2 - Hindlimbs

“…This study is the first to describe equine hindlimb kinematics during swimming and complements the forelimb data reported in Part 1 (9). Significantly lower ROM of the stifle and fetlock were observed during swimming compared with PM.…”

“…The experimental protocol was similar to the one previously utilized in the companion study on the forelimb (9). Data were collected in an indoor, 100 m long, 2.95 m wide, and 3 m deep, straight pool that allowed free swimming in a straight line over at least a 70 m distance.…”

“…Previous studies have investigated the cardiovascular (3,4), muscular (5,6), and respiratory (7,8) responses in horses during swimming. In a companion manuscript, forelimb kinematic data of swimming horses were described (9). This study reports the kinematics of the hindlimb during swimming, where it is thought to have a propulsive role (10).…”

Development of a Methodology for Low-Cost 3D Underwater Motion Capture: Application to the Biomechanics of Horse Swimming

“…The system we developed involves the utilization of waterproof cameras and surface markers drawn on the horse, along with the necessary pre-and postprocessing techniques to reconstruct and analyze the captured data. We expect to determine joint angles with a precision of 1°and also confirm a range of motion larger than that on land for all joints, except for the fetlocks, similar to what was found in [24,25].…”

“…To the best of our knowledge, only one study has been conducted on the underwater 2D movement of horses [24,25]. However, the research did not comprehensively describe the swimming cycle.…”