10/08/2025
Hoof “Leverage”
The hoofcare world has been a bit touchy lately on various topics, which I’m sure many have seen.
I even recently did a post about how I’ve seen many comments that devolve into name calling and labeling things as “wrong,” just because the person arguing doesn’t seem to want to even try to understand what is being discussed. It’s been a frustrating time to have social media.
Something that is often talked about in the hoofcare world is leverage. There are entire clinics on leverage reduction. We talk about the DDFT and soft tissue and how what we do to the foot - adding or taking away “leverage” - affects the limb. And every time there is a post on this, we have comments asking where this leverage is coming from. I’ve seen questions on this page, as well as another page I help manage, about this, and I actually wrote out a long comment replying to someone, so I thought I would adapt my comment on that post and add it here.
If this were up to me to answer these questions alone, I would be floundering for sure. Luckily we have years of research and study looking into lever arms on the joints in the hoof and above. Dr. Renate Weller, Dr. Hilary Clayton, Dr. Jenny Hagen, Professor Denoix, and others have devoted their life’s work to looking at biomechanics and how hoof length and shape affect movement and soft tissue health.
To start talking about leverage and the horse’s distal limb, we need to start with the basics - the forces that act on the horse’s limb. In the most basic sense, when a horse’s hoof hits the ground, the ground pushes back with equal force. This is called the ground reaction force (GRF). The strength of that force depends on two things: how heavy the horse is, and how fast it’s moving. In addition to that, for the sake of our discussion, what really matters for the hoof is the direction of that force, as in where it travels up through the foot and leg.
Because the horse’s leg isn’t perfectly straight, this ground reaction force doesn’t just push upward, it also creates a rotational force on the joints (especially the fetlock and coffin joints). That rotation, scientifically, is called a “moment”.
We have to define where our fulcrum is and how the force acts on it. In this case, the fulcrum is the joint, and the distance from the fulcrum (joint affected) and the line of action of the force is called a lever arm. The farther away the force travels from the center of a joint, the bigger the lever arm, and the more leverage (or torque) it puts on the joint.
Think of it like using a long wrench: the longer the handle, the more force you can apply.
If nothing resisted this leverage, the horse’s leg would buckle. To counteract it, the horse’s flexor tendons, ligaments, and suspensory apparatus on the back of the leg act like springs, pulling the opposite way. Their position around each joint gives them their own moment arms (lever arms), and they apply just enough counter-force to keep the leg from collapsing. Think of Newton’s Third Law- every force has an equal and opposite reaction - but these reactions don’t have to be on the same structure, which is why they don’t cancel each other out, and also why we can still move in various directions, despite forces reacting against each other: these forces are distributed through the body and joints in various ways.
Small bones like the navicular bone and sesamoids act like pulleys, improving the tendons’ leverage and protecting them from being overloaded.
When it comes to hoof leverage: The joint we are looking at specifically in this instance is the center of rotation of the coffin joint. In the simplest terms, the longer the toe, the more the ground reaction force shifts forward. This pushes the force farther away from the center of the coffin joint, which increases leverage (the extensor moment). The horse’s flexor tendons and suspensory ligament then have to work harder to resist that leverage and keep the leg from collapsing. That means a long toe puts more strain on the soft tissues in the back of the leg.
Now of course, anything we do to a foot has some effect- there is no “zero sum” in hoofcare. Taking a toe back will change where those ground reaction forces are distributed, as well. We often have to consider what structures in the hoof were made to absorb shock or distribute forces, and which are not.
There are a handful of studies that have looked at the forces acting on the soft tissue in the limb in relation to toe length and consideration of the center of the coffin joint (center of rotation). That’s why many hoofcare providers focus on the center of rotation when making hoofcare decisions. Of course, horses are individuals and need individual considerations, so we know there are cases that will not fit the textbook!
There is a lot more we can dive into this subject, but again, this is the most basic terms, since I’ve heard this question asked quite a bit!
You can learn and read more in this paper from Dr. Renate Weller, who has presented on this exact topic many times, as it's part of her life's work!- but this specifically is from the AAEP proceedings from 2020-
How to Evaluate Foot Conformation and Understand the Effect of Shoeing on Load Distribution - Renate Weller, Drvetmed, PhD, MScVetEd, DACVSMR, FHEA, NTF, DECVSMR, MRCVS, HonFWCF
I’m not going to pretend I’m a physicist, but I like to think I took enough physics in high school to know that there are a lot of forces that act on any living body at any given time, and those bodies are really miraculously designed to put up with a lot.. until they can’t anymore! It’s actually really amazing, when you think of it.
If you don’t want to take my word for it, or if you want to hear people talk on this subject that are infinitely smarter than I am, we will have 4 amazing clinicians from around the world sharing some in-depth lectures and demos at our Podiatry Clinic at the end of this month about biomechanics and hoof health. Our clinic is SOLD OUT, but the livestream/clinic recording option is still available! I will post the link in the comments.
