Influence of trimming, hoof angle and shoeing on breakover duration in horses

It never made sense when studies in the 1900’s did not find changes in breakover duration with shoeing techniques designed to move the breakover point further back on the foot. Breakover duration is the period during a gait between when the foot is placed on the ground to the point that the toe leaves the ground. This is the period the horse pushes against the ground to sustain forward motion. Breakover duration is considered important because it is during breakover that maximal stress is placed on the laminae, navicular area, and flexor tendons. Improved observation techniques and the realization that the effects are different for different gaits have emphasized the following:
Flat shod steel shoes fitted full vs barefoot increase breakover duration and stress on dependent structures.
Moving the shoe slightly rearward (palmar) or rolling the toes ameliorates this tendency.
Elevating the heels also decreased breakover duration and presumably stress from breakover.
This validates these techniques in therapeutic shoeing for decreasing stress on these structures and begs the question if all horses should not be shod in rolled toed shoes or other techniques that move breakover back.
DrO

Influence of trimming, hoof angle and shoeing on breakover duration in sound horses examined with hoof-mounted inertial sensors
Jenny Hagen,Ramon Bos,Joris Brouwer,Stefan Lux,Franziska Theresa Jung
First published: 16 May 2021
Abstract
Objective: Aim of the current in vivo, observational study was to investigate the effect of trimming, heel elevation and different types of shoeing on breakover duration (BreakD) with a novel, hoof-mounted inertial measurement unit (IMU) sensor system.

Methods: Ten sound, crossbred horses were examined barefoot before and after trimming fitted with an IMU sensor at the dorsal hoof wall. Additionally, application of 5° heel wedges, plain steel shoes, rolled-toe shoes and palmarly-placed quarter-clip shoes was tested. Horses were guided in a straight line on firm ground. Obtained data were speed corrected prior to calculations testing the influence of different manipulations for their significance on BreakD.

Results: Trimming had no significant influence on BreakD. Heel elevation caused a significant decrease of BreakD in walk and trot. Shoeing with a plain steel shoe resulted in a significant increase in BreakD in walk. This could be rescinded by creating a rolled toe or placing the shoe palmarly.

Conclusion: Obtained results emphasize the use of heel wedges or rolled-toe and palmarly-placed shoes to ease breakover in the context of therapeutic shoeing. Hoof-mounted IMU sensors with high resolution seem to be a practical and valuable approach to accurately examine BreakD and factors