The Effect of Girth Design and Girth Tension on Saddle-Horse Pressures and Forelimb Stride Kinematics in Rising Trot.

Overview

• This study examined how different girth designs and tension levels affect saddle pressure distribution and forelimb movement patterns in horses during rising trot.
• Researchers compared two girth types (straight and anatomical) and two tension settings (8 kg and 16 kg) to determine their impacts on saddle pressure and limb kinematics.

Background and Objective

• In equestrian sports, the saddle girth plays a critical role in securing the saddle and influencing the horse’s comfort and movement.
• Different girth designs and varying tension levels could potentially alter the pressure exerted on the horse’s back and affect limb movement, which might impact performance or cause injury.
• The study aimed to investigate how girth design (straight vs. anatomical) and girth tension (low at 8 kg vs. high at 16 kg) affect:
• Saddle-horse pressure distribution in cranial (front) and caudal (rear) regions
• Forelimb stride kinematics during the rising trot gait

Methods

• Subjects: Six horses regularly ridden were included in the study.
• Design: An unbalanced Latin-square experimental design was used, ensuring each horse experienced all four conditions — two girth types (straight (S), anatomical (A)) crossed with two tensions (8 kg, 16 kg).
• Pressure Measurement:
• A pressure mat with high spatial resolution (0.5 sensels/cm) and a sampling rate of 100 Hz was placed between the saddle and the horse to record pressure distribution.
• Pressure data focused on cranial and caudal regions of the saddle area.
• Forelimb Kinematics:
• 2D limb motion was captured via anatomical markers on the fore and hindlimbs at 240 frames per second using video recording.
• Joint angles (e.g., carpal flexion) and stride mechanics were analyzed.
• Statistical Analysis:
• Examined effects of girth type, tension, and their interaction on pressures and limb kinematics.
• Significance threshold set at p < 0.05.

Key Findings

• Girth Design and Tension Effects on Limb Kinematics:
• Overall, neither girth type (straight or anatomical) nor girth tension (8 kg or 16 kg) significantly altered forelimb movement patterns during the rising trot.
• An exception was found for carpal joint flexion, which was slightly but significantly greater in the anatomical girth at low tension (A8) compared to the straight girth at the same tension (S8).
• Saddle Pressure Distribution:
• No significant difference in mean saddle pressure between girth types in either cranial or caudal regions.
• Caudal average pressure was consistently lower than cranial average pressure at both 8 kg and 16 kg tensions.
• Increasing girth tension from 8 kg to 16 kg resulted in a significantly higher ratio of cranial to caudal pressures, indicating a shift of load towards the front (cranial) part of the saddle area.

Interpretations and Implications

• The lack of significant effects of girth design and tension on limb movements suggests that within tested parameters, these factors do not impair forelimb kinematics during rising trot.
• The notable shift of pressure towards the cranial saddle region with higher girth tension indicates that tightening the girth increases localized loading on the front part of the horse’s thorax.
• This pressure concentration at the cranial region may have clinical importance because it could contribute to discomfort, pain, or injury in the cranial thoracic back region over time.
• The slight increase in carpal flexion seen with the anatomical girth at low tension might reflect subtle biomechanical differences induced by girth shape, but this finding was limited.
• Overall, the anatomical girth and straight girth performed similarly regarding pressure distribution and limb kinematics when tension was controlled.

Conclusions

• Neither the design of the girth nor the level of tension significantly influenced horses’ forelimb stride kinematics during rising trot.
• However, increasing girth tension shifts saddle pressure anteriorly, potentially increasing risk of cranial thoracic discomfort or injury.
• Trainers and riders should consider the tension applied when tightening the girth as a factor in horse comfort and back health.
• The choice between anatomical and straight girth designs may be made based on rider preference or other considerations, as their effects on pressure and stride variables were largely similar.