Freeman Medical Musings Blog


Lingering Injuries – To Stretch or Not to Stretch?

Posted by Kendra Boswell, on July 09, 2015

Sometimes when we become injured, we still have symptoms months down the road even if we have allowed time for healing. This is a very common issue that can happen when nerves around an injury become irritated. At this point, it’s no longer the original injured tissues that need to heal, but rather the surrounding nerves. Ask anyone who has ever had sciatica (pain radiating from the buttock down the back of the leg) – it can seem to take forever to heal! Why is this? Unlike other injured tissues in the body, nerves can often be stubborn and difficult to calm down. Knowing what nerves need for healing is important for understanding how to treat many injuries that linger. 

A common misconception is that if something hurts, you should stretch it. When it comes to nerve-related pain, this couldn’t be further from the truth. The nerves in the human body are estimated to take up 2% of your total body mass. To function properly, these nerves require 20-25% of the total volume of blood your heart pumps. You can think of nerves as blood sponges – they need a lot of blood! When you stretch a nerve, you take away the blood flow, and nerves tend to get irritated when this happens. 

For example, one common injury that takes a long time to heal is a hamstring strain. When you look at an anatomy picture depicting the muscles on the back of the thigh, you see the different portions of the hamstring muscles and the sciatic nerve that runs right down the center. What do people typically do after they strain a hamstring? They stretch. If you overstretch the hamstring, you also take away blood flow from the sciatic nerve. Nerves like blood the same way that humans like food. Take away someone’s food and the person may get slightly irritated. The same holds true for the sciatic nerve when you take away blood. The number-one thing that nerves need for healing is blood flow. 

Nerves also need to be able to move freely to heal. Think of nerves like dental floss – they need to be able to slide and glide easily through surrounding tissues. In the case of muscle strains, scar tissue commonly forms to promote healing. If the scar tissue interferes with movement of the surrounding nerves, they will be prone to irritation. This is often what happens in the case of nagging hamstring injuries that linger for months. 

What is the best way to help nerves get both the movement and blood flow they need for healing? “Tissue flossing” is a technique that we use a lot in physical therapy. This involves using your hands or a massage tool to “pin down” injured tissues while actively gliding and lengthening the underlying tissues you are pinning. This serves to both break up scar tissue and improve the slide and glide of underlying tissues. Working on these things can help restore nerves back to their “pre-irritated” state and help rid the body of injuries that just don’t want to go away.