The effect of collection and extension on tarsal flexion and fetlock extension at trot.

The research paper examines the impact of different trotting styles on the strain of a horse’s suspensory ligament (SL), suggesting that extended trot could increase risk of SL injury in dressage horses.

Research Objectives and Approach

• The study aims to comprehend the influence of collected and extended trot on the movement pattern of a horse’s hindlimb.
• Four dressage horses were utilized for this study. The horses were fitted with markers and inertial motion sensors (IMS) to monitor their movements.
• High-speed video recordings of each horse trotting in collected and extended styles were captured for analysis.
• The trotting was carried out on three different surfaces: a waxed outdoor surface, a surface consisting of sand and plastic granules, and a waxed indoor surface.
• The study primarily focused on evaluating the maximal tarsal flexion during stance (part of the horse’s gait) and the distal metatarsal coronary band ratio (MTCR), which represents the extension of the fetlock (joint located in the horse’s leg).

Key Findings of the Research

• Comparative evaluation revealed that collected trot had significantly lower speed and stride length, but a longer stride duration than extended trot on all chosen surfaces.
• All the horses in the experiment exhibited less tarsal flexion and fetlock extension during a collected trot than during an extended trot.
• The reduced tarsal flexion and fetlock extension in collected trots are likely to increase the loading strain on the horse’s SL.

Conclusions and Implications

• The study points out a possible explanation for the high rate of SL injuries in dressage horses: the extended trot increases SL strain, specifically in those trained for extravagant movements.
• The implications of this research suggest that consistent use of the extended trot could be a risk factor for the development of a condition known as suspensory desmitis.
• The study concludes that suspensory desmitis could be a significant factor resulting in the prevalence of SL injuries in young horses that frequently perform extravagant movements.