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Relationship of Horse Width to Human Hip Angle: Implications for the Riding Athlete

By Michael L. Pilato MS. A.T.C. Founder Equicision

* The CHA Riding Instructor Manual Committee would like to utilize this information in the rewriting of the CHA Riding Instructor Manual currently in progress. The committee would like input, positive and constructive feedback, and any comments towards the clarity of this article. Mike, has spent years researching this topic, and the committee appreciates his efforts on this topic. Please send comments under the heading “horse to rider fit article" to: Terry Williams, CHA CHA Riding Instructor Manual Committee, chairperson at: TerryjonesT@aol.com. Thank you for your valuable input on this topic.

Historically, riding is a system designed by men, for men, taught by men, then, taught by men to women and woman to woman using principles designed for a man. Modern science tells us there are gender differences that need to be considered in the teaching of this system.

As the understanding of gender differences to performance and injury continues to improve, so do the programs and concepts to minimize the risk of injury and maximize performance of, especially female athlete, continue to improve. Such concepts and programs can be especially important to the female athlete dominated equestrian sports.

Hip pain and the ability to address on horse problems (such as not being able to sit up straight) are ongoing problems encountered by almost every instructor and rider. This article presents a very simplified approach, derived from sit-to-stand and squat research, to think about on-horse problems and hip pain.

First concept:
The horse can be thought of as a wheeled chair that the athlete (can) alternately sit and stand up from. In “normal human standing” stance width (or the width a person’s feet are apart when sitting on a chair, such as for work) is on average 6 inches from heel to heel. In sitting, this distance can increase based on comfort. Stance width has been defined in three ranges; Narrow—up to 125%, Med-up to 155%, Wide-up to180%, and Super wide >180% bi-acromial (shoulder) width.

Clearly no horse is that narrow and therein begins the solution (or problem). The equestrian athlete is always in some degree of “wide stance”. In my pilot study looking at this relationship, stance width ranged from 160-300 percent stance width. Along with this, normal end range of abduction motion, as measured when standing, is 45 degrees. Measured hip abduction angles from the pilot study ranged from 27-37 degrees.

Second Concept:
The risk of hip pathology (arthritis, etc.) and or pain increases with activities requiring increased hip flexion/abduction/landing. Landing is included due to the force transmitted to the rider via the horse.

As stance width increases, the muscles that act most to control femur position within the socket are put in a compromised position. Although gluteus maximus muscle activity is increased, that muscle is used to control torso posture and as a secondary stabilizer of the lower extremity. To that, calf muscle activity is also decreased, which further increases the force transmitted to the hip.

Third Concept:
It needs to be mentioned that the relationship between spinal body shape, hip socket and femur is really quite intimate. However for purposes of this discussion, the focus is on the relationship of the femur to the hip socket. In females, the hip joint is designed to promote flexion and internal rotation.

Why is this problematic when sitting on a horse? If hip flexion (think shortening the stirrups) is coupled with internal rotation and adduction of the femur (think putting the thigh on the horse), the lower extremity is put in a mechanically less efficient position for managing the forces transmitted to the rider through the horse.

Putting it together:
The relationship of horse width to hip abduction angle is quite easy to see. The wider the horse the greater the hip abduction angle, the greater the chance of the femur pinching/rubbing the socket. In the more experienced athlete, where the potential for arthritis or degenerative joint changes is higher, the available range of motion in the joint would be smaller, thus increasing the chance for hip pain.

The relationship to on-horse problems may be harder to see as there are many contributions. First, there  is foot position. The foot will follow in a line with the leg as abduction angle increases. To achieve the “traditional 12:00” foot position, multiple compensations of the lower extremity are used.

Second, as hip angle widens, the hip muscles that help control position of the femur in the socket are placed in a poor position in terms of creating force. This results in a loss of hip joint control.

Third is the promotion of flexion and internal rotation in the hip socket as the hip is flexed. This posture in sports medicine is known as the “position of no return” and is known to be mechanically less efficient than a “knee over foot in line with the hip” posture.

Fourth is inhibition. This is caused when the femur nears its end range of motion or when the athlete feels pain in the hip. The compression of the femur against the cartilage and or any arthritic spot creates a reflex inhibition of the muscle(s) in an attempt to decrease compression and relieve pain in the joint.

Taken together there is a general loss of efficiency in the lower extremity that begins at the hip and spreads to the whole body resulting in a global loss of whole body control efficiency.

Finding the Best Anatomical Fit:

While finding “the best horse” for each athlete is often frustrating and involves multiple factors, by taking measurements of the horse and athlete, a good anatomical match can be achieved. Measuring barrel width (in horses with two different shaped rib cages requires two half widths) on the horse and lower leg length on a person (taking 115% of that length) allows for a close estimation of hip abduction angle.


This newly created program is an attempt to help the riding athlete eliminate one variable of the many related to the problems seen on horse. By doing so, it should also provide the instructor and athlete a framework from which to address “non-horse related” problems.