Ground reaction forces and limb function in tolting Icelandic horses

• Published in: Equine veterinary journal Vol. 36; no. 8; pp. 743 - 747
• Main Authors: Biknevicius, A.R, Mullineaux, D.R, Clayton, H.M
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-12-2004
• Subjects: 4-beat gaits; Animals; Biomechanical Phenomena; forces; Forelimb - physiology; forelimbs; gait; Gait - physiology; ground reaction forces; Hindlimb - physiology; Hoof and Claw - physiology; horse; horses; Horses - physiology; Icelandic (horse breed); Icelandic horses; kinematics; legs; locomotion; Locomotion - physiology; measurement; Stress, Mechanical; tolting; tölt; velocity; Weight-Bearing
• ISSN: 0425-1644; 2042-3306
• DOI: 10.2746/0425164044848190

Summary
Reasons for performing study: Gaited horses employ 4‐beat stepping (singlefoot) gaits that extend into speeds typical of trots. Ground reaction force (GRF) patterns of these specialised gaits have not been reported; therefore, appraisal of these gaits using nongaited horse kinetics may lead to clinical misjudgements.
Hypothesis: GRFs of tölting Icelandic horses will be comparable in profile and magnitude with those of trotting horses.
Methods: Forelimb and hindlimb GRFs were obtained for 10 Icelandic horses ridden at a tölt. These data were evaluated across 3 speed ranges: <2, 2.5–5 and >5 m/sec.
Results: Virtually all vertical force tracings were single‐peaked. Forelimbs typically had greater peak vertical forces and impulses compared with hindlimbs. Support duration and forelimb vertical impulse were correlated negatively with speed, whereas peak vertical, braking and propulsive forces and hindlimb braking and propulsive impulses were correlated positively with speed.
Conclusions: GRF profiles of tölting Icelandic horses are more similar to profiles of trots than walks, suggesting that tölts follow bouncing mechanics.
Potential relevance: Greater overlap of limb support in 4‐beat gaits (even at high speeds) is associated with lower peak vertical force magnitudes of tölts compared with those reported for trots at comparable speeds, which may help limit the occurrence of overloading injuries in Icelandic horses.