Why should we care about posture in horses? Because it affects the complex interactions of the brain, muscles, nerves and skeletal system. Recognizing abnormal compensatory postures as a cause of many lameness and behavior problems is essential to improving equine health.
Normal neutral posture
Most horses spend much more time standing still than they do moving. The average domestic horse is ridden an hour a day, lies down briefly for REM sleep, but spends as much as 22 hours a day standing. Therefore, his stance can have a larger influence on body mechanics and soundness than his exercise program!
The standing posture observed in a normal, sound horse at rest is called Normal Neutral Posture (NNP). Neutral stance balances and stabilizes the body’s center of mass, allowing rapid, accurate mobilization when necessary. NNP is the functional output of sensory and gravitational information, processed through the central nervous system (CNS), and is essential for wellness in all animals, including humans. The CNS regulates the activities of the mind and body as a complex system -- an integrated, dynamic interaction of thought, nerves, muscles, bones, tendons and ligaments, as well as visceral functions, like digestion.
What does NNP look like? When horses are standing on level ground, all four cannon bones should be perpendicular to the ground. Because they are large and must be efficient, horse anatomy is specialized to allow them to use passive support to minimize the energy needed to support their weight. Having vertical limbs loads the body weight onto their bones and supporting ligaments, much like the legs of a table. Just as a table has stability in its structure, a horse in NNP does not need to use significant active muscular force to maintain stance, saving metabolic energy for other non-passive functions, like locomotion. Maximum weight-bearing during locomotion occurs when the limbs are vertical. So, standing with limbs vertical strengthens bones, muscles and ligaments most effectively to withstand the peak mechanical forces of movement.
NNP also organizes the muscles of the back, which determines the spinal contour. In neutral stance, the superficial, movement- generating muscles along the back can be soft and relaxed since deeper postural muscles are providing the necessary support. A neutral spinal contour is lowest right behind the withers, sloping gently up to the top of the croup, without a pronounced “roached back” (kyphosis) or “jumper’s bump”(steep croup or lumbo-sacral angle.)