In October 2021 I was lucky enough to attend the Centaur Biomechanics Equine Sports Seminar Virtual Summit. As always, the lectures were of a very high quality and there was an immense amount to take in. Here I share with you some of my understanding.
Professor Michael Weishaupt works at the University of Zurich in the School of Veterinary Medicine and is in charge of the Equine Perfomance Centre. His PhD in 2004 researched the compensatory mechanisms of weight bearing lameness in horses, and in 2010 this received the Venia legendi of the University of Zurich for Equine Sports Medicine and Exercise Physiology. His special interests include assessment of poor performing horses, orthopaedics, shoeing, and the biomechanics of lameness. He has published two e-learning tools, one on equine upper airway diseases (Equad) and one on shoeing and diseases of the hoof (e-hoof.com).
There are various guidelines on trimming and shoeing. The goals are not to disturb or restrict the natural movement potential of the horse, to keep the hoof and distal limb sound, and to assure durability of the shoeing. Some considerations are the mediolateral balance, the dorso-palmar / plantar balance, and the weight-bearing functionality.
In the swing phase, we need to consider limb flexion, protraction, and limb extension. In the stance phase we need to consider landing, loading, and push off including breakover. We also need to consider the gait, the speed and direction of travel, and ground surface properties.
In the swing phase, the limb flexion and protraction are due to inertial forces, which means that the weight of the lower limb has an impact on the height of protraction and the lateral / medial deviation. In the pre-impact phase, the angle of attack and speed of approach are relevant. The height of protraction can be manipulated by adjusting the weight of the distal limb. This might include the hoof conformation (hoof height, length, and the angle of the dorsal hoof wall), and weight (for example, boots).
In the stance phase, we need to consider impact attenuation, the breaking phase of the hoof, the mediolateral balance and the dorso-palmar / plantar balance. The impact attenuation can be influenced by the material that is used in the shoe. Influencing variables for the mediolateral balance in the landing phase are individual limb and hoof conformation, ground surface properties, gait, and speed of travel. Influencing variables for the dorso-palmar / plantar balance are individual hoof pastern axis and hoof angle, breed type, ground surface properties, gait and speed of travel. It is a fact that uneven landing can induce orthopaedic problems.
In conclusion, correct trimming of the foot is the first and most important aspect in terms of biomechanical considerations. Only when we have a correctly trimmed foot can we apply a horseshoe. We can apply the lever principle to avoid unnecessary torques. When we are using extensions to redistribute load, we must be aware of the risk of overloading on the side of the extension (on soft ground), or the side of the wedge (on hard ground). It’s important to address imbalance in mediolateral or dorso-palmar / plantar hoof balance, as these can lead to deformities and compensatory reactions in joint and supporting soft tissue structures.
For more information, great webinars and a whole heap of relevant research, visit www.centaurbiomechanics.co.uk.
© Sue Palmer, The Horse Physio, 2021
Treating your horse with care, connection, curiosity and compassion
