As a physiotherapist I was taught to stretch what is tight and strengthen what is weak. This is the model many therapists of all disciplines share and often obey. However, newer evidence has shifted the thought process a bit in terms of how we stretch and if we even should at all…the work of Grey Cook, Janda, Shirley Sahrmann, and Paul Chek among others has changed the landscape of stretching. I will use my own interpretation of the literature to explain in layman’s terms why stretching a “tight” muscle may in fact be the exact opposite thing you want to be doing…
Research has shown that when muscles get long they become what is known as facilitated. A facilitated muscle is one in which it receives too much neural input from the nerves that innervate it. Theories as to why this happen very. But my opinion is that long muscles get facilitated as a protective response from the body. The body is saying “this muscle is too long and might tear if pushed further so I (the brain) will increase the neural input to that muscle to keep it at a constant and steady state of increased contraction”. This increased contraction is supposed to prevent any damage to the elongated muscle…hope that makes sense. This increased neural drive to the muscle makes it SEEM tight. This is why we have the desire to stretch it because it feels hard and tight when we attempt to lengthen it. However, this muscle is NOT actually tight…it’s TENSE. There is a big difference between a tight and tense muscle. Stretching out a facilitated (tense) muscle only serves to INCREASE this neural drive to the muscle. The reason is because (once again) the brain thinks this stretched muscle is at even further risk of tearing and therefore more neural drive must be given to the muscle to make it even tighter.
Therefore, STRETCHING A FACILIATED MUSCLE WILL ONLY MAKE IT TIGHTER…which is exactly oppose of what the goal of stretching was in the first place.
Here is a common example….the oh so popular Tight Hamstrings:
A major cause for hamstring tightness is due to an anterior pelvic tilt
I won’t get into the reason for the tilt now…I’ll save that for another post lol
This anterior (or forward) tilt creates a further distance for the origin and insertion of the hamstrings. The ischial tubersosity on the back of the pelvis (origin) and posterior tibia and fibular head (insertion) get pulled further away from one another due to this pelvic tilt thus making the muscle group longer (see picture of hamstring origin and insertion)
Also, the anterior tilt places the body’s center of gravity forward slightly (also happens with forward head posture). The body doesn’t like feeling off balanced so it sends messages to the calves and hamstrings to tighten up to keep the body from falling forward…the calves and hamstrings act as pulleys to keep the body from going forward in the presence of a forward head posture and or pelvic tilt
The elongated hamstrings group in this cause becomes facilitated because of the pelvic tilt making the muscle longer. The body responds to this my increasing the neural input to the hamstrings to tighten them up (even though they are already long!). Therefore, it makes NO sense to stretch these “tight” hamstrings because that will only create more neural drive and thus more muscle “tightness”. The key to fixing the hamstring length issue in this case has nothing to with the hamstrings at all. It has to do with correcting the pelvis alignment so the hamstring origin and insertion (where the muscle starts and ends) is at a more optimal position to turn off this constant neural input.
“Find the cause and fix the problem”…..
Thanks for all the support I’ve been getting. I love what I do and hope these articles help other therapists and the general public understand and appreciate the complexity of the human body!
As always, comments and questions are ALWAYS welcome 🙂
Jesse Awenus B.A Hons (Kin), MSc.PT