Effects of Shoeing on Breakover Forces in Icelandic Horses at Walk, Tölt and Trot

Abstract

Introduction To enhance expressiveness and regularity of the tölt, Icelandic horses are commonly shod with excessively high and long hooves. The aim of this study was to objectively assess the effect of shoeing on distal interphalangeal (DIP) joint moments of the left forelimb during break‐over at walk, tölt and trot. Methods Twelve sound Icelandic horses accustomed to exercise with a rider on a treadmill were assessed with hooves trimmed and shod according to the standards of normal shoeing and with long and high front hooves; besides the 20 x 8 mm steel shoes, this condition included pads and packing material used in competition. Vertical ground reaction forces (GRFz) were measured with an instrumented treadmill. Time of break‐over was determined kinematically. Measuring systems were started synchronously; sampling frequency was 480 Hz. Measurements were taken at 1.34 ± 0.04 m/s (walk), 3.89 ± 0.10 m/s (tölt), and 3.90 ± 0.10 m/s (trot). The DIP joint moment arm was determined on size‐calibrated latero‐medial radiographs of the left front hoof. Differences were tested using a t‐test (walk) or repeated measures ANOVA (tölt, trot). Results In the condition with the long and high hooves, DIP joint moment was increased by 18.5% at walk (P<0.001), 17.3% at tölt (P<0.001) and 13.4% at trot (P = 0.017) although vertical GRFz at break‐over was not statistically different between the two shoeing conditions. The increase could be attributed to the 22.7% increase of the lever arm. Conclusions High hooves with long toes may have negative implications for the health of the palmar structures of the distal foot. Ethical Animal Research The experiment was carried out with the approval of the Animal Health and Welfare Commission of the Canton of Zurich (No. 206/2010). Owners gave informed written consent. Sources of funding: Stiftung Forschung für das Pferd, the Haldimann Stiftung, the Swiss Metall Union, the Stiftung Temperatio, the Swiss Veterinary Office (FVO) and the Islandpferde‐Vereinigung Schweiz. Competing interests: none.

Passive Dynamics Explain Quadrupedal Walking, Trotting, and Tölting

“…5(c) and 5(d)). This may be caused by the comparatively larger range of the limb angle in Icelandic horses compared to Warmblood horses; especially while t€ olting [25,26].…”

Science in brief: Highlights from the biomechanics and physiotherapy abstracts at the International Conference on Equine Exercise Physiology

“…Weight, particularly in combination with high and long hooves, increased protraction height, but increased limb peak forces marginally . However, high hooves with long toes may have negative implications for the health of the palmar structures of the distal foot, because the distal interphalangeal joint moment increased significantly , and enhanced inertial forces during the swing phase might stress internal distal limb structures .…”

Hoof conformation in Icelandic competition horses and its interrelationship with hoof pathologies and tölt performance

“…In spite of this improvement of performance, this shoeing style may be problematic from a biomechanical perspective as it contradicts standard principles of balancing hooves. A longer toe results in a longer lever arm during break-over, prolongs its duration and increases the distal interphalangeal joint (DIPJ) moment in both ICE (Weishaupt et al, 2014) and Warmblood horses (WB) (Clayton, 1990). The higher DIPJ moment during break-over increases tension within the deep digital flexor tendon (DDFT) and its accessory ligament, and compression of the navicular bone (O'Grady and Poupard, 2003;Page and Hagen, 2002).…”