A Case Study in Core Stability and the Hidden Causes of a Hollow Back

The jockey described the horse as feeling like he was stuck in one gear.

No matter how much he asked, the horse struggled to quicken or lengthen. Transitions between canter leads were awkward and the whole stride felt slightly flat through the back, as though the horse couldn’t quite organise his body underneath the saddle.

It wasn’t dramatic resistance. The horse wasn’t bucking or refusing.

But something clearly wasn’t right.

When this happens, the first step is always to rule out pain, and the vet had already assessed the horse and given him a full soundness check. Clinically he was considered sound.

And yet the rider could feel the body wasn’t functioning the way it should.

Alongside the change in performance, there was another detail that everyone had started to notice.

Every time the horse worked, his tail was held firmly to the left side of his body.

It stayed there consistently, ride after ride.

On its own that might seem like a small thing, but horses rarely hold their tail in a fixed position without a reason. The body is usually compensating for something deeper within the system.

Situations like this are incredibly common in performance horses. The horse is technically sound, but the movement no longer feels fluid or organised.

When I watched this horse move for the first time, the tail confirmed what everyone had already seen. But what interested me more was how the rest of the body was moving around it.

Instead of the back lifting and swinging softly through the stride, the ribcage appeared quite rigid. The horse could still move forward, but the movement lacked the elasticity you expect when the core system is working properly.

Over time I’ve learned that horses reveal a lot about their body through patterns of movement. If you watch carefully enough, those patterns begin to form what I call a movement map.

Every horse carries one.

A movement map is simply the collection of compensations a horse develops to protect weakness, restriction, or instability somewhere in the body. If you look closely enough, those patterns will often tell you exactly where the system is struggling.

To understand this horse’s movement map, I began asking him to perform a few simple movements from the ground.

Nothing complicated.

Just walking, turning, and then rein back.

The Movement That Revealed the Problem

Rein back is one of the most revealing movements you can ask a horse to perform.

To step backwards correctly, the horse must lift the ribcage, activate the abdominal system, stabilise the pelvis, and coordinate the diagonal pairs of limbs. In other words, the horse must organise the core of the body.

When this horse stepped into rein back, everything became clear.

Instead of stepping backwards softly, the movement quickly became disorganised. His head lifted into the air and the ears flattened slightly. One hind toe dragged along the surface and the rhythm broke down within just a few steps.

Most importantly, the back never lifted.

The horse was trying to move, but the body simply couldn’t organise itself.

This is often the moment where riders realise the problem isn’t training at all.

The horse isn’t refusing the movement.

The horse can’t stabilise the body enough to perform it correctly.

Where the Weakness Was Sitting

Once the rein back highlighted the issue, the next step was to understand where the restriction was sitting.

With this horse the weakness was centred behind the saddle, through the thoracic spine and into the pelvic girdle.

This region plays a crucial role in stabilising the horse’s core and allowing the hind limbs to step underneath the body effectively.

When tension or instability develops there, several compensations begin to appear:

The back struggles to lift.

The spine begins to hollow slightly.

The hind legs lose the ability to engage underneath the body.

And the horse braces through the neck and tail in order to keep moving forward.

From the saddle this often feels like a horse that is stuck in one pace, unable to change gears easily and slightly crooked through the body.

Which was exactly what the jockey had been describing.

The horse wasn’t unwilling.

The body simply lacked the stability needed to organise the stride properly.

Restoring the Core

Once we understood what was happening, the goal was not to work the horse harder.

Instead, the focus shifted toward helping the horse reconnect with the muscles responsible for stabilising the back and pelvis.

We introduced a small number of targeted exercises that the rider could perform both before and after work.

These movements were simple, but they encouraged the horse to release tension through the thoracic region and begin activating the abdominal system again.

When the correct muscles begin to wake up, the spine can finally start to lift and stabilise.

Sometimes the most effective changes come from the smallest adjustments.

Ten days later I returned to reassess the horse.

Ten Days Later

The first thing I asked the horse to do again was rein back.

The difference appeared almost immediately.

Where the rein back had previously looked uncomfortable and staggered, the horse now stepped back in clean diagonal pairs. The back lifted gently and the head remained soft and relaxed.

There was no toe dragging and no tension through the ears or neck.

The horse was finally able to organise the movement through the spine and pelvis.

Rein back is such a powerful indicator because it quickly reveals whether the horse can stabilise the core. If the back is restricted, the movement falls apart. When the system begins functioning again, the difference becomes obvious within a few steps.

But the most interesting feedback came once the horse returned to work under saddle.

The jockey reported that the horse had done his best piece of work.

For the first time in weeks the horse could change gears easily, the canter felt straighter, and the whole stride felt lighter through the back.

Even the tail that had been clamped to the left had disappeared.

Nothing dramatic had been forced. The horse had simply regained the ability to organise his body correctly.

What This Means for Riders

Cases like this are far more common than many riders realise.

Many horses that appear weak, resistant, or one-paced are not lacking strength. Often they have simply lost the ability to stabilise their core effectively.

When the back becomes restricted, the horse compensates in subtle ways. Over time those compensations show up as changes in performance, straightness, and willingness to push forward.

Once the restriction is addressed and the correct muscles begin to activate again, the whole system often starts to function much more freely.

The horse isn’t suddenly becoming stronger overnight.

The body is simply working the way it was designed to work again.

Signs Your Horse May Be Struggling With Core Stability

If you’re curious whether your horse may be experiencing something similar, a few common signs include:

• difficulty changing gears or lengthening the stride

• a hollow or rigid feeling through the back

• the tail consistently carried to one side

• rein back feeling awkward or disorganised

• transitions that feel sticky or resistant

These patterns often appear long before more obvious issues develop.

When we learn to recognise them early, we can help the horse restore balance and stability before the problem progresses further.

Want to Learn How to Spot and Release This in Your Own Horse?

On April 4th I’m hosting a Live Hollow Horse Audit, where I’ll walk through real case studies like this and show riders how to identify the early signs of a horse bracing through the back.

During the session we’ll look at:

• how to recognise the small movement signals that reveal core instability

• why some horses hollow through the spine even when they are technically sound

• simple exercises riders can use to help their horse release tension and begin lifting through the back again

If you’ve ever ridden a horse that feels one-paced, hollow, or difficult to organise through the body, this session will help you understand what may be happening biomechanically.

You can learn more about the Live Hollow Horse Audit on April 4th here.