Ever wonder why you’re not becoming more flexible even though you stretch? Did you know there is mechanism in your body that detects stretching and tells the muscles to resist the stretch?
The muscle spindle stretch receptor is a cell in the heart of every skeletal muscle (i.e., NOT smooth muscle such as in your stomach). Its job is to detect stretching in the muscle. When it does, it sends a message through the spinal cord–it doesn’t even reach the brain. The message reads “Hey, we’re stretching now!” Upon receiving the message the spine sends instructions back to the muscle to contract.
Wait, I thought we were stretching. Why on EARTH would the muscle contract?
The purpose of this automated feedback loop, called the spinal reflex arc, is to protect you. It’s a default setting to prevent injuries if something were to happen unexpectedly. If you were to fall and you braced yourself with your left hand, your shoulder may be pushed back really far really fast. The muscle of concern, which would likely be the anterior deltoid in this case, immediately receives a message of stretching and before you even know it, that muscle is resisting the stretch and pulling the shoulder forward again. Injury is mitigated, but of course not necessarily avoided. The body does its best to keep us safe.
This is really important for us when we’re stretching. If your stress levels are very high or you are being too aggressive, this feedback loop is going to be harder to disarm. The muscle spindle stretch receptor can also become oversensitive and overreact, but as far as it is concerned it’s responding appropriately (YES that is a life metaphor!). This can cause increased stiffness in the body and makes stretching less effective and more likely to cause injury.
The autonomic nervous system needs to believe that you are in a safe setting or it’s going to be reluctant to let you stretch. But it’s the autonomic nervous system–it’s unconscious. We have to work through the somatic nervous system (voluntary action) to communicate with the autonomic nervous system. Buckle up buttercup!
So how do you get the nervous system to cooperate?
1. Proper warmup. A systematic warmup tells the body that we are doing intentional training. The more times you do this, the more quickly the body sets itself for the activity.
2. Massage tools. Tools like the peanut can be used to prepare muscles for stretching. You can also use a foam roller to help release tension in the body.
3. Stress reduction. Whether through breathing, meditation, massage, spending time with animals, or being outside, frequently, intentionally reducing stress is going to be helpful for disarming this feedback loop when you want to stretch. This is part of what makes flexibility a holistic practice. It feeds into and draws from many different areas of your life.
4. PNF. Proprioceptive Neuromuscular Facilitation is the practice of gently contracting and then relaxing the muscle you want to stretch. This helps dissolve the block created by the muscle spindle stretch receptor.
5. Breathing while stretching. Lengthening and deepening the breath triggers a cascade of messages through the body and also increases blood flow and oxygen levels. It helps muscles reduce their contractile states.
6. Be intentional. Flinging your foot into your hand for 5 seconds after you run is not enough to give your quads and psoas the care they need.