You have both involuntary and voluntary nervous systems. You do not control your autonomous nervous system, which works of its accord. This system includes all the inner working parts of your body that help regulate your digestion, heart rate, and breathing rate, among other mechanisms. On the other hand, the somatic nervous system controls your voluntary bodily movements. This system includes all the muscles and body parts you can consciously move. However, this voluntary system is also responsible for involuntary somatic reflexes.
When we test these reflexes, your reaction might be greater than expected, lesser than expected, or non-existent. Your reaction can point to certain conditions. Let us explore your four main somatic reflexes and how they work to protect you.
How do Somatic Reflexes Work?
You have sensory nerves that connect directly to your spinal cord. This immediately triggers a muscle reaction. These reflexes are so immediate because they travel to the spine directly and do not have to pass through the brain.
Harmful situations can activate these nerves, which then work to protect you. Other times, the situation is not necessarily harmful but still triggers a reflex. The classic knee reflex test is such an example. Your physician taps an area just below the knee, causing your leg to kick out.
When left untreated, certain conditions, such as diabetes, can lead to sensory nerve damage. As a result, you might feel numbness or pain, leading to less sharp reflexes.
The Stretch Reflex
In situations where you overstretch, this reflex helps to prevent you from injuring yourself. Muscle spindles are receptors that receive and send information about muscle length. When you stretch, you are lengthening the muscle. Your spindles send a message to your spine, which tells your muscles to contract. For instance, if you slip and your foot starts to go out from under you, your thigh muscles contract and help you avoid a groin injury.
The Golgi Tendon Organ Reflex
This reflex is the counterpart to the stretch reflex. Instead of causing your muscles to contract, your golgi tendon organ relaxes your muscles. The golgi tendon organ is another receptor that measures tension on your muscles. If you are exerting too much tension, your GTO prevents you from creating any more force.
The Withdrawal Reflex
This is probably the reflex you are most familiar with. When you experience harmful or painful stimulation, your body immediately draws back. This happens because your flexor muscles contract and your extensor muscles relax. For example, if you accidentally touch a boiling hot pot, your muscles immediately jerk your hand back.
The Crossed Extensor Reflex
The crossed extensor reflex goes hand in hand with the withdrawal reflex. If you withdraw a limb, your crossed extensor reflex extends the opposite limb to help support you. Let us say that you step on a sharp block or needle barefoot. Your foot instinctively draws back and your other foot immediately supports all your body weight.
Sharpen Your Reflexes
If you experience issues with these reflexes or want to improve them, reach out to a physical therapist who understands your somatic mechanisms. We can work together to help sharpen your reflexes and elevate your athletic performance or everyday life.
Carol Montgomery, MSPT, GCFP, STMI, is a dedicated, passionate Physical Therapist whose focus is on the somatic relationship between the physical body and the psyche for rehabilitation and recovery. She is also a co-creator of Integral Human Gait™ Theory and a Guild Certified Feldenkrais Practitioner and Movement Intelligence Senior Trainer. She is a graduate of both the Indianapolis Gestalt Institute and the Institute for Integrative Psychotherapy.