Ground reaction forces and limb function in tölting Icelandic horses.
Authors: Biknevicius A R, Mullineaux D R, Clayton H M
Journal: Equine veterinary journal
Summary
# Ground reaction forces and limb function in tölting Icelandic horses Tölting—the distinctive four-beat singlefoot gait of Icelandic horses—represents a significant departure from conventional equine locomotion, yet force analysis of this specialised gait had been absent from the literature prior to this 2004 work. Biknevicius, Mullineaux and Clayton collected ground reaction force (GRF) data from ten tölting horses across three speed ranges (<2, 2.5–5, and >5 m/sec) to characterise how their limbs manage loading during this gait. The results revealed predominantly single-peaked vertical force patterns with forelimbs consistently bearing greater peak forces and impulses than hindlimbs; notably, support duration and forelimb impulse decreased with speed whilst peak vertical forces and braking/propulsive forces increased with speed. Unlike the mechanics of walking, tölting force profiles closely resemble those of trotting—indicating a "bouncing" mechanism—yet the extended limb overlap characteristic of four-beat gaits produces substantially lower peak vertical forces at comparable speeds than true trots, likely conferring a protective effect against overloading injuries. For practitioners managing Icelandic horses and other gaited breeds, this work underscores that interpreting tölting limb function through a trot or walk paradigm risks clinical misinterpretation; the gait's inherent biomechanical design may actually explain the breed's apparent resilience to high-speed work-related injury.
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Practical Takeaways
- •Tölt should be evaluated using trot-based kinetic models rather than walk-based models, as the biomechanics are fundamentally different despite the 4-beat footfall pattern
- •Lower peak vertical forces in tölts compared to trots at similar speeds may explain why Icelandic horses can maintain this gait at extended speeds with reduced injury risk
- •Forelimb loading predominates during tölt; practitioners should monitor forelimb structures (especially distal forelimb) for signs of cumulative overload despite the gait's apparent injury-sparing mechanics
Key Findings
- •Tölt ground reaction force profiles are more similar to trotting gaits than walking gaits, indicating bouncing mechanics despite being 4-beat gaits
- •Forelimbs generate greater peak vertical forces and impulses than hindlimbs during tölt
- •Peak vertical, braking, and propulsive forces increase with speed while support duration decreases with speed
- •Greater limb support overlap in tölts produces lower peak vertical forces compared to trots at comparable speeds, potentially reducing overloading injury risk