[Paper Review] Three-dimensional Torques and Power of Horse Forelimb Joints at Trot

Hilary M. Clayton, Daohang Sha+1 more|arXiv (Cornell University)|Aug 19, 2011

Veterinary Equine Medical Research13 references3 citations

TL;DR

This study presents a three-dimensional inverse dynamics analysis of horse forelimb joints during trot, using a simplified link-segment model to calculate 3D torques and power across the elbow, carpal, fetlock, pastern, and coffin joints. Key findings show that 70% of total energy generation occurs during the stance phase, with the elbow contributing 77% of generated energy in stance and 88% in swing, while the fetlock absorbs 65% of energy during stance and the carpus 74% during swing.

ABSTRACT

Reasons for Performing Study: Equine gait analysis has focused on 2D analysis in the sagittal plane, while descriptions of 3D kinetics and ground reaction force could provide more information on the Equine gait analysis. Hypothesis or Objectives: The aim of this study was to characterize the 3D torques and powers of the forelimb joints at trotting. Methods: Eight sound horses were used in the study. A full 3D torque and power for elbow, carpus, fetlock, pastern and coffin joints of right forelimb in horses at trot were obtained by calculating the inverse kinetics of simplified link segmental model. Results: Over two third of energy (70%) generated by all joints come from stance phase, and most of energy generated was by elbow joint both in stance (77%) and sway (88%) phases. Energy absorbed by all joints during stance (40%) and sway (60%) phases respectively is not a big difference. During stance phase, all most two third of energy (65%) absorbed was by fetlock joint, while over two third of energy (74%) absorbed was by carpus joint during sway phase. Conclusions & Clinical Relevance: This study presents a full 3D kinetic analysis of the relative motion of the humerus, radius, cannon, pastern and coffin segments of the forelimb at the trot. The results could provide for a more sensitive measure for kinetic analysis.

Motivation & Objective

• To extend equine gait analysis beyond 2D sagittal plane studies by incorporating full 3D kinetics.
• To quantify 3D joint torques and power generation/absorption in the forelimb during trot.
• To improve sensitivity in kinetic analysis for clinical and biomechanical evaluation of equine locomotion.
• To identify dominant joints responsible for energy transfer and absorption during stance and swing phases.

Proposed method

• A simplified link-segment model was constructed to represent the forelimb segments: humerus, radius, cannon, pastern, and coffin bones.
• Inverse dynamics was applied to calculate 3D joint torques and power using kinematic and ground reaction force data.
• Motion data were collected from eight sound horses trotting on a treadmill.
• Joint power was computed as the product of joint torque and angular velocity in three orthogonal planes.
• Data were analyzed across stance and swing phases to differentiate energy generation and absorption.
• Statistical analysis focused on phase-specific torque and power magnitudes and distributions across joints.

Experimental results

Research questions

• RQ1 Which forelimb joints contribute most to energy generation during the trot gait in horses?
• RQ2 How is energy distributed between generation and absorption across the elbow, carpal, fetlock, pastern, and coffin joints?
• RQ3 What are the relative contributions of each joint to 3D torque and power during the stance and swing phases?
• RQ4 How does the distribution of energy absorption differ between the stance and swing phases?
• RQ5 What is the role of the elbow joint in overall forelimb kinetic behavior at trot?

Key findings

• Seventy percent of total joint energy generation occurs during the stance phase, with the remaining 30% during the swing phase.
• The elbow joint contributes 77% of energy generation during the stance phase and 88% during the swing phase, making it the primary contributor.
• During the stance phase, 65% of energy absorption is attributed to the fetlock joint, while the carpus absorbs 74% during the swing phase.
• Energy absorption during stance (40%) and swing (60%) phases is relatively balanced across all joints.
• The carpal joint is the dominant absorber of energy during the swing phase, indicating significant dynamic control.
• The study provides a comprehensive 3D kinetic profile of forelimb joints, enabling more sensitive clinical and biomechanical evaluation of equine gait.