Designed to Work Together

One of the major consequences of chronic contraction and motor-sensory amnesia is that muscles stop functioning in relationship to one another the way they were designed to.

Muscles are meant to work in coordination.

When one muscle contracts and shortens, its partner should lengthen and yield so movement can occur smoothly and efficiently.

Then they switch roles.

This alternating relationship is what creates fluid movement but chronic contraction changes that relationship over time.

Two important things can happen that interfere with healthy function: stretch weakness and reciprocal inhibition.

Stretch weakness occurs when one muscle remains chronically shortened, mechanically trapping its partner in a lengthened position.

A muscle held in a chronically lengthened state loses its ability to generate force effectively and it begins functioning as though it is weak.

This is important because the issue is not necessarily developmental weakness.

At the same time, there is also a neurological component occurring through reciprocal inhibition.

Normally, when one muscle contracts, the nervous system automatically sends inhibitory signals to its antagonist so the opposing muscle can relax and stay out of the way of the movement.

This process allows muscles to take turns efficiently but when a muscle remains chronically contracted, those inhibitory signals continue as well.

So now the opposing muscle is dealing with both a mechanical disadvantage and ongoing neurological inhibition.

It is being lengthened mechanically while simultaneously receiving signals discouraging contraction.

Over time, this significantly changes how the horse is able to organize movement and because these patterns become habituated within the nervous system, the horse often no longer perceives them consciously.

This is one reason why compensation patterns can persist long after the original injury, stressor, or protective response has resolved.

The nervous system has adapted to the pattern and now recognizes it as familiar.

In Equine Hanna Somatics, we aim to restore awareness so the horse's nervous system can regain the ability to sense that other options exist.

** This image illustrates a classic agonist-antagonist relationship. If everything is functioning smoothly, when the biceps contract, the elbow is flexed and when the triceps contract, the elbow extends.