Horse Bio-Mechanics

Kirsten

Some of the common indicators that people use to determine if a horse is moving correctly include:

  • An arched neck with the head on the vertical
  • Lengthening the stride so the horse is over tracking its front hoof prints
  • Light or no rein contact or steady, even heavy, rein contact
  • Fast speeds or exaggerated movement
  • The fact that the horse can perform a maneuver or job

None of these common indicators however prove or disprove balance, or correct bio-mechanical use of the horse’s body. They may be present once balance is achieved, but the presence of any one of these peripheral indicators in no way guarantees that a horse is moving in correct balance.

From Dr. Gavin Scofield:

“Because a body is a closed system, balance or imbalance in one part will always affect the rest of the body. In other words, true balance cannot be faked, or indicated in isolation. Every part of the body must be functioning correctly, appropriate to each form, or the entire body will be out of balance.”

Appropriate use of the body can more reliably be assessed through the observation of weight load distribution. If the horse in motion shows excessive weight bearing through the front legs, then the horse is not functioning correctly no matter what the frame, head position, stride length, speed or ability the horse appears to convey.

Weight distribution indicates how forces are controlled by the back muscles and general structure of the horse. While a horse is quite capable of compensating to make appendages (head, neck and legs) appear “correct”, weight distribution actually confirms or denies the correctness of the movement. Compensation patterns for overall imbalance then become obvious.

When a horse learns to balance equally side to side and control its body weight during motion using the back muscles and hindquarters, then the popular indicators take shape as a result. A perfect frame, lengthened strides, power, speed and efficiency in maneuvers or jobs are the end result of balance, but not always the means to balance.

When trying to assess if a horse is moving correctly, it is helpful to know some basic functions of the overall body to further understand why body weight control during motion is so important.

Head and Neck
The head and neck are used by the horse to recover balance or compensate for a loss of balance through the back and legs. The neck is extremely mobile and flexible so the horse uses it to compensate for a loss of balance or for  regaining balance much like humans use their arms. The chosen head and neck position of the horse is a reflection of the current use of the back and hindquarters. An unstable head and neck position simply reflects poor use of the back or instability in the hindquarters.

How this affects training:
“Setting” the head and neck or overly restricting movement with devices or rein contact can inhibit the horse’s ability to find or maintain balance. A rein contact should offer a horse support or guidance from the rider while still allowing a natural range of motion. When the horse is able to freely alter its head and neck position the rider gains true feedback about the horse’s back use and the stability of the hindquarters.

Front Legs
The front legs are attached to the horse’s skeleton only with soft tissue. A horse does not have a collarbone like a human that attaches the arms to the rest of the skeleton. Instead the sling of muscles and soft tissue that connects the horse’s front legs to its body supports the position of the legs and allows an extensive range of motion.
The general shape, organization of joints or angles of the front legs are straighter compared with the hind legs. This design allows the front legs to act like pillars for stationary weight bearing while a horse is resting or grazing. During motion the design of the front legs also shows us the weight load must fall straight through the front legs or they will be compromised. The stance phase of the front legs should be directly vertical to gravity, vertical under the shoulders. During movement, the front legs reach forward to cover ground. This mobility can only be achieved if the horse’s body weight is controlled by the back muscles and stability of the hindquarters. If the front legs are excessively loading with too much weight they cannot effectively reach forward and the stance phase of the stride will occur behind a vertical alignment. When the horse’s weight is excessively on the forehand in motion, the front legs will not reach forward very far and the stance phase of the stride will be at a backwards angle. If extending or lengthening a stride is forced, and does not reflect actual weight control through the back, then the front legs can reach forward too far forward causing the stance phase to occur while the front leg is ahead of vertical, at a forward angle. If the forward, backward swing of the front legs is not equal, then the stance phase of the front legs will not be vertical and damage to the front legs can occur.

How this affects training:
Resting a majority of body weight on the front legs while stationary or grazing is a natural state for a horse. Since domestic horses lead a sedentary life compared to wild horses who move an average of 25 miles per day, domestic horses seldom discover how to shift a majority of weight off their front legs during motion. It is important that the training program includes teaching a horse how to coordinate the back muscles in motion between forward forces and controlling body weight from falling forward to the front legs. Without active help, domestic horses will most likely continue to function with an inappropriate amount of weight on their front legs, even while being ridden.

Hind Legs
The angular positioning of the bones and joints in the hind legs compared to the front legs allows the hind legs to act as levers or a stabilizing area of the body during motion. As the horse pushes the hind legs extend backwards, behind the torso. As the horse brakes or controls forward motion the hind legs extend forward, closer to the center of the body. The hind leg joints flex twice and extend twice between the stance phase. The forward movement of the hind legs during the braking phase allows the body to stabilize in motion and helps control body weight from falling forward to the front limbs. The equalization of the hind leg movement between braking and pushing is controlled by the use of the back muscles and spine.

How this affects training:
More speed and longer stride lengths are not always “better” and we can cause imbalance when we adopt the beliefs that “faster = better” or “slower = better”.  In other words, equal is better. Some horses may need to slow down and shorten the stride for a time in order to improve balance through control during braking. Other horses may need to increase speed or pushing power to equalize the phases of the stride. Allowing a horse to choose its speed and stride length is a good starting point. As we slowly increase or decrease speed and stride lengths we will feel where the hindquarters become  more stable during motion.  By equalizing the forward and backwards motion of the hind legs first, at any speed or stride length, the entire hindquarter becomes stable first which allows the horse to then gain more power and agility. 

The Back
The horse’s spine and use of the back muscles is command central that determines the specific use of the head, neck, front legs and hindquarters. The muscles of the back, above the spine, have attachments to the bones of the spine in opposing directions. When the muscle use is equalized between braking (control, stability, weight management) and pushing (forward forces, speed, and lift) the spine flexes upward to “lift the back” which then alters the exact flight path and use of all four legs and stabilizes the use of the head and neck. The back muscles must be supple enough to lengthen and strong enough to contract in length or eccentric contraction to flex the spine upward or lift the back upward and create suspension of the front end.

The muscles above the spine and the muscles closest to the vertebrae control the function of the spine. If the  hindquarters and back are not the source of stability for the horse in motion, then the back muscles will shorten and contract in order to create stability with dysfunctional use of the spine. If the spine itself is not stable, making the entire back unstable, then the horse will overly contract the muscles around the front legs and neck to find stability. No clever use of reins or bits or clever use of the whip to affect the legs will create balance as long as the front end of the horse is doing the work of stabilizing the body in motion.

How this affects training:
If the back is too tight or tense the muscle will shorten instead of lengthen. This can have the effect of restricting the position and stability of the entire hindquarter, impeding engagement. If the back muscles are not strong enough to sustain flexion and control internal body weight through resistance, then adding the extra weight of a rider can make balance very difficult for the horse. The back of the horse must be both strong and soft for the horse to function correctly with the weight of a rider. This is why groundwork can be so important to successful riding.

Spine
The spine runs from the back of the skull through the horse’s top line, right into the tail. It is part of the axial skeleton and the midline of the horse’s entire body. The spine needs to be stable in order for the entire horse to function correctly. As the spine lengthens and becomes laterally stable in a healthy alignment, it becomes easier to flex upward or suspend. Each vertebra in a horse’s long spine moves in minuscule amounts but each movement is critical. If one joint of the spine is corrupted with too much flexion, too much extension, misaligned or is laterally rotated out of place, then the entire spine is compromised and its ability to act as one unit becomes extremely difficult. When each segment of the spine is able to operate freely, then the joints can align appropriately, extend slightly and the entire spine can then act as one unit. Correct upward flexion of the spine creates an overall impression of roundness in the horse’s posture during motion without unnatural looking curves in any one section of the spine. The spine itself does not “round” but instead flexes upward into a neutral, straighter alignment. The suspension of the spine creates more suspension in the horse’s movement, making the entire horse look and feel lighter in motion. The frame of the horse will become slightly more compact from nose to tail, but this cannot be forced first in order to correctly flex the spine. A horse with correct or mechanically ideal use of the spine appears to move with ease and has natural and comfortable looking curves to the overall posture.

How this affects training:
The functions of the spine become the primary focus of training. There are five different functions possible in the horse’s spine and all need to be guided into optimal coordination for the whole horse to find balance in motion. Various uses of the head, neck and legs can alert us to the current use of the horse’s spine, but we cannot find optimal use of the spine by stimulating, manipulating or influencing the use of the limbs, neck and head. It works the other way around. Finding stability through the midline of the horse, as a geometric straight line of force even during turns and circles is just the first step of guiding the horse’s spine into better function. Excessively bending the neck and shifting the barrel side to side is one of the most common ways that we inadvertently cause dysfunction of the spine with the thought that we are somehow “suppling” the horse. 

Muscular System
The muscles throughout the horse’s body will develop to support the habitual function of movement. Whether the horse’s function has been correct or incorrect, the muscles will develop and strengthen to sustain the habitual use of the body. A horse that has been functioning correctly will have smooth, symmetrical muscular development without obvious peaks and valleys from nose to tail. A horse that has been functioning with too much weight on the front legs as a habit will appear more developed and stronger on the front end compared with its hind end. The muscular development of the horse is the result of habitual function. Muscles gain strength through contraction and gain suppleness through relaxing. A balance of strength and suppleness, with a muscle moving though its full range of motion, is what allows the body to move with maximum power and flexibility. A horse that has been habitually functioning out of balance will have a lack of muscle development in some areas and excessive muscular tension, or a lack of suppleness, in others.

How this affects training:
In the beginning stages of restoring a horse’s healthy function from unhealthy function, time and patience are required. When a horse has built muscle around patterns of incorrect function, then excessive muscular tension must be released first, restoring a full range of motion to each muscle. This can be an uncomfortable feeling with lots of instability during the process. As the coordination of the skeleton changes, or the posture changes, new muscles will strengthen to support the new habits of movement. During the process of change, the horse may begin using muscles that are very weak or atrophied from previous lack of use, and so training will be slow. Changing postures and functions can mean that the horse tires more easily during work or can do less in work before fatigue sets in, especially during the early stages of change. Once the muscles recondition to support correct function, the horse will have more stamina and power than ever before. Starting slow and paying attention to correct use of the spine is what ultimately strengthens the muscles in the right way for a horse to become powerful, agile and light. 

Getting to know just a few of the basic mechanical functions can change the way we think about training our horses. The design of the body is what tells us about correct function. We either learn to work with it or we suffer with horse “problems” from behavioral issues to vet bills for lameness. Understanding our horses just a little goes a long way to achieving our goals in riding.

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