Part 1
Have you ever heard these phrases?
Your horse:
needs more hindlimb engagement.
is lacking push from behind.
is too heavy on the forehand.
is weak behind.
has a weak canter
Today, I am going to explain what this all means, to give you clarity and understanding of why your horse might be suffering from any of the above symptoms.
First, let’s define what we mean by “HINDLIMB ENGAGEMENT”.
If you google it this is what comes up:
Engagement is the bending of the hind-leg joints, specifically articulation of the pelvis, stifles, hocks and fetlocks, enabling the horse to shift his weight off his front end and carry more weight behind.**
**google2023
To be honest, I used to align with this belief before delving deep into equine anatomy and its impact on movement—or more precisely, how form influences function.
I used to assume that if my horse lacked hind limb engagement, there must be issues in the stifles, hocks, fetlocks, or hooves (perhaps all of them!). Calling in the vet and therapist, nine times out of ten, we'd discover issues with the stifles or hocks. Despite inconclusive radiographs, my horse would often receive steroid injections, swiftly followed by a return to training.
To be frank, albeit varying between horses, the effects of the steroid injections were typically short-lived. While I did notice subtle improvements in my horse's ability to engage, they were fleeting. I found myself repeatedly discussing my observations from a riding perspective with the vet, farrier, and therapist. Regrettably, their responses echoed the same suggestions:
Steroid injection, again
Saddle change
Hill work
Pole exercises
Instead of gaining insight into why my horse struggled with hind limb engagement, I ended up feeling overwhelmed and perplexed, lacking a concrete plan of action.
In the past, questioning a Vet felt almost unthinkable, right? After all, why would you doubt their expertise?
Until a few years ago, facing a Vet would make me nearly forget my own name!
Fortunately, I've evolved since then. I won't claim perfection, but years of delving into horse anatomy, working with hundreds of horses across the UK, and trusting in my abilities have transformed me. Now, I always ask questions! No matter who I'm talking to, if something isn't clear or I don't grasp it, I'll ask for an explanation—always seeking the 'why'.
If there's a key takeaway from my page and content, it's this:
"Anatomy expertise isn't essential (you're not expected to have it), and being an expert isn't your role (that's what professionals are for). However, always inquire! Stand up for your horse. If you're uncertain about a diagnosis or don't completely agree with it, always seek clarification. Ask 'why'."
Let's delve back into understanding equine hindlimb engagement.
Here's my grasp of what enables your horse to engage it's hindlimbs:
We can't disregard the interconnectedness of the entire body. For optimal movement and performance, it's crucial for our horses to move without discomfort. The ability of our horses to engage their hindquarters doesn't solely rely on the stifle, hocks, fetlocks, and hooves functioning optimally. It's also governed by a muscle group known as the iliopsoas (refer to Image 1 below).
Image 1: Protraction phase of the hindlimbs
During the protraction phase (when bringing the hindlimb forward), the iliopsoas plays a vital role as a potent flexor of the coxo-femoral joint. Additionally, it's involved in external rotation and adduction. When contracted, it initiates lumbosacral flexion, triggering the lengthening of the middle gluteal and caudal femoral muscles. Image 2 illustrates the contrasting action during hindlimb propulsion.
Image 2: Hindlimb propulsion.
Stay tuned for an in-depth exploration of the iliopsoas muscle group and their functions in an upcoming blog post...
Before we proceed, let's talk about the elephant in the room: the Sacro-iliac (SI) joint (refer to Image 3 below).
In my opinion, this joint is often over-diagnosed due to a lack of understanding of its function. I won't delve too deeply into it in this blog because this joint deserves its own dedicated page!
In summary, the SI joint operates on a shearing force, not compression force (unlike the hock or stifle). Its primary function is to transfer forces from the hindlimb to the TL vertebral column, ensuring stability. Palpating it from the surface is quite challenging (veterinarians can perform rectal ultrasonography).
Around the SI, three robust ligaments—dorsal, ventral, and interosseous—contribute to stability and shearing force.
Now, here's a thought: Despite horses often receiving SI injections for signs of "poor hindlimb engagement," considering what you've just learned about the form and function of the SI versus the iliopsoas, could these horses have been misdiagnosed? I'm not discrediting the possibility of SI joint injuries affecting pelvic stability, but in many cases, the form and function of the iliopsoas might be overlooked.
The journey with horses is a rollercoaster of highs and lows. Even after dedicating over 25 years to the equine industry, I continue to see myself as a perpetual student. Embracing this open and curious mindset helps me keep my ego in check and acknowledges that learning is a constant process.
This concludes part 1. Stay tuned for part 2, where I'll delve into and share the exercises I recommend for enhancing a horse's hindlimb engagement.
Any questions?
Email me on: info@animalchiropractoruk.com