The Importance of the Psoas Muscle
The Psoas muscle runs from the horse’s lumbar spine and attaches onto the Femur (Hip bone) and blends with the iliacus muscle to form iliopsoas. This incredible muscles contains very little fascia as it is a non-weight bearing muscle and you would probably have come across it as one of the most expensive cuts of meat in the butchers - a fillet steak (because it is so pure).
The function of the psoas is hip flexion (bringing the horse’s hind limb up and underneath them) and it also stabilises the spine. Additionally it enables the horse to engage the hindquarters correctly by flexing the lumbar spine and pelvis due to its unique location underneath the spine.
The Psoas muscle can become injured when the horse slips and the hind limb slides backwards fast, gets stuck in deep mud and has to pull the leg out forcefully, if the horse falls or if a young horse is pushed into an outline too fast/too young or worked incorrectly.
Psoas injuries can present as:
an inability to engage the hind end, the horse will struggle to half halt, will jump very flat or twist in the air to avoid the discomfort. They may also feel very choppy in canter due to lack of flexion through the lumbar spine and pelvis.
Heavy in the hand then ridden as the horse transfers the weight forwards
Dragging the hind toes, landing toe first or plaiting behind as they struggle to pick up the hind limb correctly
Struggle to back up as they struggle to drop the weight back into the hindquarters
Standing “parked out” or very wide behind
Psoas is also a very important muscle for riders and has been implicated in low back pain in humans. Those of us with desk jobs spend most of our day sitting down and so our psoas spends a lot of time in a shortened position, causing it to tighten over time. When you then get on your horse, your tight psoas will pull the pelvis forward, causing the lower back to arch and making it difficult to engage your pelvis properly and you won’t be able to move smoothly with your horse’s movement, especially in canter.
Whether horse or human, most acute muscle strains will heal over time on their own or with a little help. For more chronic issues, although we can’t reach the psoas muscle directly, working on surrounding muscles and fascia, as well as getting the lumbar spine and hip moving can help. And of course laser can get deeper into the tissues and help promote muscle relaxation and healing.