Every month I review my client's reports and reflect on my findings and their progress. Without a shadow of doubt the muscle group that is most often overlooked amoung horses (both sports performance and amateur ridings) is the Iliopsoas.
Before I share my reasonings; let's look at the function of this group of muscles:
Anatomy:
The Iliopsoas muscle group is comprised of the Psoas Major, Psoas Minor and Iliacus muscle (image 1 below). It is responsible for the stability of the spine and pelvis.
For those of you that prefer a visual representation, the iliopsoas is the filet mignon or pork loin in animals. It is a tender and usually harvested as two long snake shape cuts of beef (see image 2 below). It is a non weight bearing muscle and therefore contains less connective tissue compared to other cuts.
Image 2: Filet mignon (wix images).
Function:
The Iliacus and Psoas Major, composing the Iliopsoas, share similar muscle functions, including:
Protraction of the hindlimb
External rotation of the hindlimb
Flexion of the hip (coxofemoral) joint
Stabilization of the vertebral column when the hindlimb is stationary.
This muscle group connects the trunk to the hindquarters, facilitating engagement of hindlimb muscles while maintaining proper posture. Understanding the role of the Iliopsoas underscores the necessity of its correct and healthy function for efficient hindlimb protraction.
Let's take a step back and think about this....
As a rider, what is the number one thing we want in a horse? We want engagement of the hindquarters. No matter which discipline! The main focus of training is to encourage horses to come off of their forehand, through developing pelvic stability and strength.
During the swing phase (non weight bearing phase) of the hindlimb stride, flexion of the hip (coxofemeral joint) lifts the entire limb and brings it under the trunk by TWO muscle groups through concentric contraction (shortening the muscles): see image 3 below.
1. Iliopsoas, which flexes and brings the hindlimb forward as well as flexing the lumbars and pelvis.
2. Crainal femoral muscle group (TLF and rectus femoris muscle).
Image 3: showing the muscle involved in the protraction phase of the hindlimb
Hindlimb engagement is initiated by the iliopsoas through flexing of the lumbosacral region and hip joints. The abdominal wall muscles contribute to engagement by flexing the thoracolumabr and intervetrebal joints.
Common Signs of iliopsaos dysfunction include:
Asymmetrical hindlimb muscle developement - potentially causing loss of muscle tone to Iliopsoas muscle group
Inconsistent contact due to compensatory locomotive patterns.
Unequal hindlimb protraction which can be associated with a "Hip drop/hike” on the side of injury as hindlimb flexion is limited.
Bilateral shotening of the hindlmbs
Reluctance to "sit" in the canter
Heavy on the forehand
Tail carried to the uninjured side.
Unable to pick their feet up in walk or trot - dragging their hindlimbs
Hard time backing up - if they drift to one side (this is the injuried side)
Toe ticking in walk and trot (different to toe dragging).
Toe stab when walking - toe heel when walking (due to no flexion of their pelvis)
Interferring behind (plaiting movement)
The canter - no flexion in the pelvis, short strides behind - difficult to sit to.
Lack push from behind (like you are riding two horses)
The above are only some of the symptoms I have seen out at field.
Please ensure that you are taking regular postural pictures and videos of your horse in walk, trot and canter. Monitoring is the best way to highlight any subtle changes of discomfort and pain that your horse may be masking.
Iliopsoas dysfunction on back function:
Sensitivity of the lumbar region and behind the saddle area can be due to iliopsoas dysfunction. This in turn will affect your horse's ability to engage their core. They can be ridgit and stiff showing you signs of discomfort when you are asking for relaxation over their back or movement through the ribcage.
Causes of iliopsoas dysfunction:
Trauma - slip and falling
Damage to the fascia around the lumbar region
Seasonal stringhalt
Ill fitting tack
Foot balance
Inadeaquate warmup
Pushing young horses who haven't stopped growing to carry a frame- compressing their posture.
Incorrect training
Imbalanced riders
How to prevent Iliopsoas dysfunction:
Avoid the above causes! From a management perspective:
Appropriate warm up
Gymnastic Exercises in hand and under saddle
Postural training early on
Regular physical therapy
Breed dependant- therefore monitor their posture and skeletal growth slowly.
Avoid gadgets for a forced pressure - making your horse lower its head and neck more will cause MORE strain on the iliopsoas as this muscle has to stabilise the back and pelvis.
Extreme changes in terrain
Treatment of iliopsoas dysfunction:
Work with a Vet and team of professionals that are open minded and treat holistically
Regular physical therapy
Alter their training accordingly
Thank you for reading and if you have a question, please email me:
Thanks,
Nika x