Mechanical and functional properties of the equine superficial digital flexor tendon.
Authors: Dowling B A, Dart A J
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Mechanical and Functional Properties of the Equine Superficial Digital Flexor Tendon Dowling and Dart's 2005 review synthesises in vitro and in vivo evidence on how the superficial digital flexor tendon (SDFT) functions mechanically and adapts throughout the horse's life. The authors highlight a critical distinction: adult SDFTs operate with minimal biomechanical safety margin during maximal exercise, leaving them vulnerable to fatigue failure when microdamage from work and age accumulates, yet mature tendons show limited capacity for positive adaptive remodelling. Conversely, foals demonstrate greater plasticity—those given free pasture exercise developed larger, stronger, more elastic tendons than confined or formally trained counterparts, with differences attributable to non-collagenous matrix changes rather than collagen alone. This suggests that early exercise prescription (type, intensity and timing) and the mechanical signals it generates during skeletal maturation may fundamentally determine lifetime SDFT durability. For practitioners, the implication is stark: inappropriate early training or excessive work may permanently compromise tendon biomechanics in young horses, whilst well-designed developmental exercise programmes could create substantially more injury-resistant structures in adult performance animals.
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Practical Takeaways
- •Unrestricted pasture exercise in foals promotes superior tendon development compared to formal training programs or confinement—prioritize free movement during growth phases
- •Controlled exercise timing and intensity during early development may be critical for building injury-resistant tendons, as excessive or inappropriate training can cause permanent biomechanical damage
- •Adult horses have minimal capacity to improve tendon strength through exercise, so injury prevention through appropriate workload management is essential
Key Findings
- •Adult superficial digital flexor tendons operate near functional limits with narrow biomechanical safety margins during maximal exercise
- •Foals allowed free pasture exercise develop larger, stronger, more elastic tendons compared to confined or trained foals
- •Mature equine superficial digital flexor tendons show limited adaptive ability to exercise, whereas foal tendons demonstrate greater adaptive potential
- •Non-collagenous matrix composition appears responsible for differences in tendon properties between exercise conditions in foals