The Withdrawal Reflex
Afferent Input provides a common understanding of the beneficial effects of all the physical therapies, from reflexology to yoga, chiropractic to physiotherapy, Qi Gong to aerobics, Pilates to Shiatsu.
Any practitioner who touches, moves, pokes, prods, adjusts, manipulates or mobilises a patient is altering that patient’s afferent input.
Consider reflexology. When a reflexologist rubs or stimulates points on the feet they are activating sensory receptors in the skin, fascia and muscles of the feet, just as a pebble in the shoe would do. If you had a pebble in your shoe, you would stop and remove it or you would move differently as the muscles that would normally push your foot to the floor are inhibited and the ones that lift your foot off the pebble are facilitated. Although the leg may not move and the limp may not be visible in the early stages, there will be facilitation (increased activity) of some muscles and inhibition (decreased tone) of others.
A reflexologist is stimulating deep touch receptors in the feet but tickling the foot would stimulate the same reflex via light touch receptors. Tickling around the neck, under the arms or around the tummy would provoke the same reflex, facilitating some muscles while inhibiting others.
While reflexology and tickling have a real effect on muscle tone, those effects are short-lived. The facilitation and inhibition are normalised as soon as the stimulation is removed.
The same is not true of a foreign body.
In this example, a belly piercing is causing inhibition of the Quadratus Lumborum and other spinal stabilisers.
Acupuncture can likewise be explained in terms of skin receptor stimulation. This time the insertion of needles induces the withdrawal reflex just like reflexology does except this time the needles’ effects will be more specific and far more powerful than simple pressure on the skin because the needle may physically damage free nerve endings. The stimulation from those nerve receptors may last hours to days after the needles are withdrawn.
Afferent input offers an alternative explanation for the practice of acupuncture and leads us to look for the effects of other foreign bodies we commonly leave in the skin.
A nail in the foot is the classic example of the withdrawal reflex, but a nail through the ear or the nose will also produce facilitation of some muscles and inhibition of others.
This woman’s nose piercing was causing inhibition of her neck flexors and over-facilitation of her neck and also her low back extensors.
It is impossible for an earring not to induce muscle tone changes as the body withdraws from the irritating foreign body. Once we are aware that these changes are inevitable, it would be negligent not to examine for it as long as the examination is appropriate for inhibition.
Afferentinput.org offers a FREE course which helps health professionals really understand how reflexes alter musculoskeletal function in ways that affect their patients and paid courses on how to examine muscle tone and restore it to normal quickly, permanently and effectively.