The withdrawal reflex
Posted by · Leave a Comment
The withdrawal reflex (also known as the flexor withdrawal reflex) also exists to keep us safe.
Whenever our skin is stimulated, our muscles respond appropriately to remove us from harm’s way.
This reflex can be stimulated by a wide variety of factors.
- Heat (touching a hotplate)
- Sharp (standing on a tack or a thorn)
- Deep pressure (a pebble in your shoe)
- Light pressure (tickling your foot)
When this reflex is activated, certain muscles contract to pull us away from the source of the irritation. Naturally, (according to the Law of Reciprocal Inhibition) when any muscle contracts, it’s antagonist must be at least partially inhibited.
In other words, our skin is almost hard-wired into our muscle system (via sensory reflexes and the nervous system).
Most of the time, this sensory stimulus is transient and our muscles return to normal as soon as the threat is lifted.
But sometimes the threat stays. Sometimes the stimulus becomes permanent.
If I were to poke you in the stomach, you would flinch. No matter how much you exercised or how fit you were, your abdominal muscles would contract and your back muscles (the antagonists) would be inhibited.
If I then made that reaction permanent by leaving the irritation in place in the form of a belly piercing, then it would only be a matter of time before the back gave way in the form of a strain, sprain, pain, sciatica or disc bulge.
You can see the unsafe results of this safety mechanism in the following videos.
The first shows a young lady with 2 years of low back pain. As she stimulates the piercing, her low back inhibition vanishes (our body is more sensitive to changes in stimulation, than stimulation itself)
In the second video a young dancer tells us what happened the day after she took her piercing out
Belly stud in a dancer
Whether or not a piercing induces inhibition is largely a matter of luck. It depends on which nerve endings are stimulated. It would appear that metal of all kinds is the worst nerve ending stimulator. Often if the piercing is replaced with nylon, teflon or wood, the inhibitory effect of the piercing is lost.