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

Abstract

BackgroundSwimming is used for rehabilitation and conditioning purposes in equine sports medicine. We described the swimming kinematics of the equine forelimbs in Part 1. The aim of Part 2 is to assess stifle, tarsus, and hind fetlock joints kinematics in swimming horses. The objectives were 1- to calculate and compare joint angles during swimming against passive mobilizations (PM), 2- to determine joints angular velocities during a swimming stride cycle.MethodsEleven elite endurance horses were used to swim in a 100-meter 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 metatarsal epicondyle, lateral aspect of the talus, lateral femoral epicondyle, and great trochanter of the femur. As a reference, maximal fetlock, tarsus, and stifle flexion/extension angles were determined during PM overground. Differences between angle extrema, angular velocities, and range of motion (ROM) were statistically compared.ResultsThe tarsus ROM was similar during PM and swimming. The stifle and fetlock ROM were greater during PM, although the stifle flexion was greater during swimming. The stifle and tarsus had the greatest hindlimb angular velocity during the swimming cycle. Greater angular velocities were observed during the retraction phase for all the hindlimb joints.ConclusionA short retraction phase with great angular velocity for the joints of interest characterized the swimming pattern observed. Swimming may be beneficial in horses when an increased ROM of the tarsus and stifle or a reduced fetlock extension is indicated for rehabilitation purposes.

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, this study is the first to record and analyze these two proximal joints during swimming. When comparing the results obtained for the maximal flexion and extension angles, as well as the range of motion (ROM), with the existing literature on horse swimming for the other three joints in each limb [24,25], the findings are consistent. However, several factors may account for the differences observed.…”

“…This could potentially have resulted in less diversity in the results. Secondly, in our study, the angles were measured in 3D, whereas Santosuosso et al used 2D angles in their investigations [24,25]. This distinction may have introduced variations in the results, as the out-of-plane component was not accounted for in the 2D measurements, particularly for the hind limb, which undergoes outof-plane rotation.…”

“…However, several factors may account for the differences observed. Firstly, our study included a smaller sample size of six horses and twelve recordings, which was half the number of horses examined in the study conducted by Santosuosso et al [24,25]. This could potentially have resulted in less diversity in the results.…”

“…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.…”