Human Anatomy II - The Female Pelvis
By Jochen Schleese

Human Anatomy II

In the article "Who's Built Best to Ride?" we touched upon some of the anatomical differences between men and women, which could ultimately lead to inherent differences in riding capability (not Ability) simply because of how we are built. In this continuation, we will go into detail of how and why the structure of the female pelvis can influence your position on a saddle, and how we can counteract this in the saddle design.

For example, the more inward curvature of the spine a woman has, the more tipped forward her pelvis is going to be. This lower back hyperextension is a perfectly normal trait, and is most exaggerated in gymnastics. However, the most important thing here is that the position of the back dictates how the stomach and back muscles work to complement each other. The interaction of these muscles make it possible to comfortably walk, run, or even stand. If either of these muscle formations is stronger than the other, the effects will be felt in the spinal column. This can range from a backache to nerve damage. It just makes sense then, that if the position of the frame is muscled a particular way to accomplish any other athletic endeavor, then it has to be in that same position when you are riding a horse. Simply put, ride the way you are muscled. If that means you have an extremely hyperextended lower back, then ride that way. Excelling in your discipline is going to be hard enough without having to worry about the position you are forced to sit in - don’t adapt to the saddle, have the saddle adapt to you.

In the next example, the word “collapsed pelvis”, is going to be used. To avoid confusion here, there are two ways to collapse your pelvis; side-to-side, and front-to-back. For this segment of this article, collapsed means a pelvis, or hip, that is tipped back. However, for a woman who normally has a hyper-extended back, even a straight pelvis would be considered collapsed; meaning that in this particular frame she has lost the muscular influence of the stomach muscles. A woman with a very hyper-extended/tilted pelvis is forced to sit straight in
her saddle, because of the pressure of the pommel against her pubic bone. Because she will be fairly unable to use her stomach muscles in this position, her weight will be pushed to the rear of the saddle.

“Bring your legs back”. “You're slouching”. “Shoulders back”. These are the typical resulting comments from the trainer. And here is the explanation why - as the hip collapses backward, the legs, which are attached by muscles from the hip, will naturally follow the same alignment. Here it would be forward. To support the lack of balance that the hip has given the frame, the shoulders compensate by coming forward. Pure and simple, the position of the pelvis will dictate the position of the legs and shoulders.

To complicate matters further, when your frame results in slouching forward with your upper torso, your reins will have to be supported with tension from your biceps. Biceps are muscles that are supposed to be used for a short duration i.e., lifting a glass to your mouth, combing your hair, etc. However, when that muscle is required to work against a constant force, it promotes tension. In weight training, this would be a curl; lifting a weight from your knees to your chin. When that weight is constantly moving, a body builder could be working with 100 lbs of weight. However, if he were asked to hold that weight motionless, with his upper and lower arm at 90 degrees, 10 lbs of weight would soon become very heavy.

When a rider is sitting upright, the arms should become very relaxed. It is the whole upper torso, supported by the rider's interactive stomach muscles and back muscles (which are designed to support this constant tension), which will transmit the sense of relaxation to the horse through the reins. The most interesting aspect of this collapsed pelvis is the resulting "travel" of the hip. When stomach muscles are under-developed and used for counter-support, one is forced to sit to the rear of the saddle. With underdeveloped stomach muscles the energy of the moving horse is only poorly absorbed. In the rising trot, the cantle becomes a trampoline, throwing the pelvis forward with the motion of the horse’s impulsion. This increased distance that the hip is thrown forward, is a greater distance than back to the saddle. These distances need to be equal to achieve that all-important requirement - Rhythm!