Straight Talk: Understanding Crookedness, Back Pain, and Body Lameness

Does your horse feel stiffer on one rein? Does the saddle slip to one side? Do canter leads feel easier in one direction? These are signs of crookedness. This means your horse is “hollow” on one side and “stiff” on the other. Crookedness is an imbalance that affects posture, comfort, energy use, and long-term soundness. Often, crookedness and performance issues relate to back pain or weak muscles, not just leg injuries. Research shows that horses with back pain show patterns similar to humans with low back pain. Let’s look at how your horse’s body works, why pain can cause crookedness, and how you can help.

Power vs. Elasticity: Big Muscles and Springy Tendons

A horse moves with strong, central muscles, while elastic tendons fine-tune its limbs. Think of the horse’s hindquarters and core as the “engine.” These large muscles have long fibers that create powerful forces to propel the body. They help control posture and joint position. In contrast, the lower legs have smaller muscles but long, spring-like tendons. These tendons act like rubber bands, storing and releasing energy. This design reduces the work muscles do when moving the limbs. Big muscles create thrust and balance. Lower limb tendons add elastic recoil. This helps the horse gallop or jump without getting tired.

In practical terms, your horse’s power comes from its core and hind end. The legs are built for efficiency and shock absorption. If there’s an issue in the core, like weakness or pain in the back or pelvis, the horse’s movement will suffer. This can lead to subtle “lameness” or an uneven gait, even if the legs are fine. The problem often lies in the body’s musculature or spine. Good movement requires harmony in the whole system.

The Equine Back: Long Muscles vs. Short Stabilizers

The horse’s back has a complex set of muscles called epaxial muscles. They work similarly in horses and humans. These muscles fall into two main groups: long superficial muscles and short deep muscles. Long back muscles, such as the longissimus dorsi and iliocostalis, have long fibers. These fibers stretch across several vertebrae. When they contract together, they extend or “hollow” the back. If they contract on just one side, they help bend the spine toward that side. Because they cover multiple vertebral joints, their effects are broad. They can’t isolate movement to a single spinal segment.

Short deep muscles, such as the multifidi, sit next to each spinous process. They consist of many small overlapping muscles that span only one to a few vertebrae. These muscles act as local stabilizers. They fine-tune the intervertebral joints and control subtle movements. The deepest layers of multifidus have short fibers. These fibers connect one vertebra to the next. This gives precise control over small motions and shear forces. The slightly longer fibers in the outer layers influence the spine's overall orientation. In essence, these muscles keep each spinal link aligned and supported.

When a horse or human gets ready to move, the body activates the multifidi and deep abdominals. This stiffens and protects the spine. They anticipate the motion and prevent the back from wobbling during movement. If the deep stabilizers aren’t working well due to pain or disuse, the larger muscles try to take over. However, they aren’t designed for fine control of individual joints. This difference is key to understanding how back pain can disrupt a horse’s movement.

When Back Pain Makes a Horse Crooked

Horses with back pain often show a pattern like people do. The deep stabilizer on the injured side shuts down. Meanwhile, larger muscles on the opposite side go into protective spasm. Veterinarians have found through ultrasound that the multifidus muscle shrinks at the affected spinal segment when there’s back pain. In one study, severe changes in a vertebra linked to significant loss of the multifidus on that side. Muscle wasting happens because of pain. Nerves stop the multifidus, making it weaken fast. This has also been shown in human back injuries.

A horse often tightens its long back muscle to make up for lost stability in the small muscles. This acts as a splinting mechanism. You might feel a hard, rigid band of muscle along the topline. Contracting the longissimus can stiffen the area. However, it locks the back in a hollowed, braced position. This does not truly stabilize the individual joints. One study even showed that increased muscle tone in the back creates more stress on the spine than a rider’s weight does. In other words, the horse’s effort to guard the painful area can actually increase strain on it.

So, how does this cause crookedness under saddle? When a horse braces one side of its back, it bends away from that side. For example, if the right side of the back is tight or painful, the horse will look hollow to the right. The right side muscles contract while the left side stretches out. This is similar to what dressage riders call a stiff vs. hollow side. The hollow side’s muscles are shorter and less elastic, while the opposite side’s muscles are over-stretched and tense. The hollow side is where the horse wants to bend, making the stiff side harder to move.

Top-view of a horse that is hollow (concave) to the right side. The body is curved rightward, with the hindquarters displaced right (arrows). The right-side muscles are contracted, and the left side is bulging outward. A horse like this will resist bending left.

When a horse is crooked from back pain, you may spot several signs in different areas:

• Head and Neck: The horse struggles to flex its neck toward the stiff side. For example, if the horse is hollow to the right, it has trouble bending left. Muscles on the right side of the neck are tight and resist stretching. This often leads the horse to avoid contact on the right rein and overbend to the right. Bending to the hollow side is easier, but when asked to bend left, the horse may tilt its head or resist.

  
  

• Thoracic Spine and Ribcage: Most side-to-side bending happens around the withers and ribcage. The mid-back (around T13-T16) bends the most. The back end of the thorax and lumbar area are less mobile. A hollow-right horse curves its thoracic spine to the right. This compression affects the ribs on that side, making them bulge on the left. On a left circle, this horse tends to “fall out” through the left shoulder because it can’t curve its ribcage left. On a right circle, it may overbend the neck to the right but push the left shoulder out. The overall effect resembles a banana curved to the right.

  
  

• Lumbar, Pelvis, and Hindquarters: The lumbar spine can only bend sideways a little. It is the least flexible part of the spine. However, it helps with rounding and hollowing. Horses have small joints in the lumbar area that allow some up-and-down motion but not much side bend. If one side of the lower back and pelvis is in spasm, the horse struggles to move its pelvis to the opposite side. For instance, a horse hollow to the right often has tight right hip flexors and back muscles. This makes it hard to step the hindquarters to the left. This horse can swing its haunches easily. However, it struggles to engage the right hind leg under and toward the left. It may also load the opposite hind limb more to avoid weight on the painful side. Over time, this uneven loading can cause secondary soreness or hoof imbalances in the overused limb.

  
  

All these signs show a horse protecting one side of its back. If the back issue isn’t fixed, the horse’s performance and comfort will suffer. Many horses get treated for hock or stifle lameness with injections. They may seem to have hind limb lameness but show little improvement. Often, the real problem is in the back or SI region. If the crookedness comes from a back or pelvic issue, just medicating a hock won’t help.

How to Help a Crooked Horse with Back Pain

Good news! Proper management and exercises can help horses with back-related crookedness. Dr. Hilary Clayton and her team found that to help a horse’s back, you must stabilize the spine, restore flexibility, and build balanced strength. Here are some strategies for horse owners and riders:

1. Veterinary Assessment: First, get an equine veterinarian or physiotherapist involved. They can diagnose issues like spinal arthritis (“kissing spine”), sacroiliac strain, or deep muscle injury. Identifying pain is crucial; you can’t fix what you don’t know exists.

   
   

2. Stretch and Activate Core Muscles: Use dynamic stretches to help your horse stretch its neck and back. A popular method is baited stretches, or carrot stretches. For example, lure the horse to bring its chin to its chest, then between its knees, or around each hind leg. The horse actively reaches, flexing and bending the spine. Studies show that doing these stretches a few times a day, a few days a week, can strengthen the multifidus muscles. Aim for consistency: about 5 repetitions per stretch, 3 days a week. The lower the horse stretches its head and neck, the more it works its back muscles. So, encourage deep and relaxed stretches. Many horses love these “yoga” sessions. They’re perfect before riding or after workouts.

   
   

3. Straightening & Flexibility Exercises: To fix crookedness, gymnasticize the horse evenly on both sides. Focus on movements that address both the hollow and stiff sides. For a hollow-right horse, stretch the tight right side and supple the left. Helpful exercises include:

   • Circles and Bends: Work on large circles, gradually decreasing the size as the horse loosens. On the stiffer bend, like a left circle for a hollow-right horse, focus on ribcage flexion. Don’t just bend the neck. On the hollow side (circle right), use a slight counter-bend or leg-yield. This helps stop overbending the neck and keeps the shoulder from falling through. This helps develop better alignment.

     
     

   • Cavaletti or Poles: Ground poles in the arena are a fun way to improve flexibility and posture. Space out poles at walk or trot distances. As the horse steps over them, it engages its core and lifts its back. You can set poles on a curve or fan to encourage bending, or slightly raise one side to promote symmetry. Poles help the horse think about each step and loosen the joints. Keep the pace slow and relaxed.

     
     

4. Holistic Care: A crooked horse often benefits from a team approach. Evaluate saddle fit, as an ill-fitting saddle can cause or worsen back pain and asymmetry. Remember that as the horse’s muscles develop, the saddle may need adjustment. Physiotherapy and chiropractic treatments can relieve pain and reset muscle tone. This makes exercises work better. Don’t forget the rider; a crooked rider can make a horse crooked. Assess your own symmetry and balance. Lastly, keep your farrier informed, as uneven movement can lead to uneven hoof wear. Good farriery supports the horse as its posture changes. By addressing all these factors, you set your horse up for success.

If your horse is showing signs of crookedness, or if something just hasn’t felt quite right under saddle, this is the perfect time to take a closer look. Crookedness is often your horse’s way of coping with back pain or weak stabilizing muscles, and early support can make an enormous difference in their comfort and long-term soundness.

If you’d like a thorough evaluation of your horse’s back, posture, and biomechanics, book an appointment with The Zen Vet. Together we can uncover the root of the imbalance, support healthy movement, and help your horse feel straight, strong, and comfortable again.

Additional Reading & Resources

If you'd like to learn more, here are some trusted articles, books, and resources to explore:

• Limb Lameness vs Body Lameness: A Farriery Perspective. Retrieved from thefarrier.co.uk

• McGowan, C., Stubbs, N., & Clayton, H. (2007). Equine Back Pain Reviewed from a Motor Control Perspective. Retrieved from ResearchGate

• Muscle-Tendon Stresses and Elastic Energy Storage During Locomotion in the Horse. Retrieved from madbarn.com

• Straightening the Horse. Retrieved from yourdressage.org

• Kinematics of the Equine Thoracolumbar Spine. Retrieved from madbarn.com