Once you have a sense of balance when the horse is in motion, you are ready to coordinate this into what I call the following seat. I'm going to introduce you in this chapter to the movement of your horse's body and how you can best coordinate with it instead of interfering. I'll start with ground exercises, then move on to some mounted work, but first I need to lay down an anatomical foundation. I tell my students to "ride with their bones," which allows the muscles to do their parts easily and with maximum efficiency. Riding with your bones requires an understanding of skeletal anatomy--where the bones are and how they articulate.
Knowing the Bones
Pelvis and lumbar area: The pelvis consists of the sacrum and the two ilia. The sacrum, composed of the last five spinal vertebrae fused together, forms the back of the pelvis, and the ilia forming the two sides wrap around to the front where they attach at the pubic arch. These bones are so firmly attached to each other by ligaments that they seem to be a single solid structure shaped somewhat like a bowl. The sockets of your hip joints lie on both sides of the pelvis. The balls at the end of your femurs (thigh-bones) fit into these sockets. The pelvis hangs on the hip joints much like a hammock supported by your legs. The dense, heavy bone at the bottom of the pelvis helps to stabilize it. Your hip joints not only supportyour entireerect weight, but they, along with the joints in your knees and ankles, permit immense flexibility.
The weight of your torso coming down from the spine through your sacrum lands somewhat behind the upward support and thrust of your legs. This construction contributes a slight shock-absorbing capacity to your pelvic region. This shock-absorbing mechanism continues throughout the length of your spine, with the forward curve of the lumbar area, a backward curve in the thoracic (rib cage) vertebrae and another forward curve in the cervical (neck) area.
These are all moderate curves that provide a cushioning effect for your back. If any of the curves is too pronounced or too straight, your back suffers stress and works inefficiently. If you hold yourself in a swaybacked posture (lordosis), the lumbosacral joint is placed directly above the hip joint. This very common posture eliminates nature's intended shock absorber,producing jarring and pain.
Conversely, if you push your lumbar spine into a roached, or slumped, position you have a different, more difficult problem: The tucked-under pelvis locks you on the back of your seat-bone "rocking chair rockers" without the slightly forward curve of the supporting spinal cushion. Thus correct positioning of your back, starting with your pelvis, is important for your balance, resilience and comfort.
Although your center and your center of gravity are not the same thing, they are located in the same pelvic area, explaining why your center must be over your feet (or your feet under your center) in order for you to be in balance. Test this out while you are standing upright, feet somewhat apart, with your hips, knees and ankles bent. This position is similar to the half-seat on your horse. Notice that your center remains over your feet. If it did not, you would fall over. Move back and forth between a deep, upright seat and a half-seat, and notice how your three joints adjust and coordinate to give you a soft balance while in motion. You will notice when you bend your joints into your half-seat that the distance your hip joints move back is the same distance your knees move forward. The movement is distributed equally between the joints.
The muscle attachment between the pelvis and the rib cage is important to your posture. The greater psoas muscles run from the front of the lumbar spine across the front of the pelvis and attach to the upper inner thighbone. The diaphragm crosses the torso below the rib cage, arcing up into the chest cavity with a big root attaching to the lumbar spine. The fibers of the diaphragm's root intermingle with those of the top of the psoas. This means that breathing with the diaphragm can help engage the psoas muscles, a very important influence on your seat, balance and posture.