Yoga as Lifestyle Medicine – The Science of Stretching for Flexibility

Do you believe that when you stretch for flexibility, stretching harder, even longer, you will increase your range? It is a commonly held belief that this may assist you in becoming more flexible, but is it true? The main reason that people begin a yoga practice is for flexibility, but if we train in a way that promotes “stretch harder and longer”, we may just be damaging our tissues.

So how do we practice for flexibility, without damaging tissue, and also increase strength at the same time?

What about when we already have a hamstring injury? How should we approach that and is it wise to just stretch it out?

New concepts around the science of stretching will change the way you view flexibility and its merits.

Do you have a limited range of motion, or flexibility issues?

When you practice yoga or stretching, if you really want improvements, then you must keep muscles active and strong with some resistance against the length of the stretch. You need to create muscle force at this range of motion that you choose in a posture. It is not passive stretching, rather active stretching with comprehensive understanding and use of Bandha’s. Your body has to be in control and awake, not passive.

When flexibility is the issue, passive stretching is not the answer. This can apply to some forms of yoga, where you have long holds and no co-activation of the muscles around the joint complex and no awareness of how to maintain tension across a joint. Best to instead move frequently in fuller ranges of motion, incrementally increasing the load on muscles. Experienced and well trained yoga teachers and therapists will be able to help you reduce the risk of tearing or injury, incrementally increasing the load on tissues. Stopping the stretch before you reach your full range is important and also increasing tensile load on the tissues, similar to strength training.

Strength training at your range of motion in each posture is important. This is superior to passive stretching; as a lack of range is not really about the length of your muscles, but rather tolerance in the nervous system. Your nervous system takes good care of you to prevent injury. For example if you are stretching beyond your normal range, and you have never stretched in that range of motion before, your body and nervous system will not understand and just won’t go there. It is your nervous system that limits your range of motion; so it is an issue of tolerance rather than mechanical length. To explain further – under anaesthesia, you would have full range of motion!

When you are dealing with limited range, or flexibility issues, you need to stretch to the point of tolerance in a gentle way so the nervous system feels comfortable and you can relax into the stretch. The stretch should only be held 30 seconds to 1 minute. In this way you should start to see good results. Your neuromuscular system will start to work in cooperation with you.

How does someone get “tight” in the first place?

“Tight” means a limited range of motion, meaning you can only take your joint in certain positions. This happens most of the time, because it hasn’t been used there, so the nervous system doesn’t recognize the movement. The muscle fibers may not yet be strong enough to maintain that force regulation through the body, so we do need to strength train as well in each posture. The joint will only move to where it is safe (and we hope not beyond!). It is not about being “tight”, or having tight muscles…it is about getting your muscles and nerves to communicate, through strengthening and stretching together.

Stretching an injury?

People who are in pain should just leave it alone instead of stretching it and instead move it and use it so the muscle fibers will direct the loads where it’s supposed to go. If you have a tendon or ligament tear, you must wait for some time before you stretch it. Having had a painful injury around the hamstring myself, I can tell you that underuse was a much more appropriate way of healing it rather than overuse! The biggest problem we face with acute injury is that when the inflammation goes down after the initial injury, we may not feel it as being a problem and go straight back to stretching, but collagen takes up to 6 weeks to heal. A more conservative measure would be 1-2 years! People may only hear this advice about stretching after consistent re-injury to the tissues.

Think about it…If you tie two hair bands together and one is more elastic than the other, then the more elastic band (or more compliant) will stretch further. It is the same with muscles and surrounding connective tissues. If you stretch a stiff hamstring muscle, but the connective tissue we call the tendon at the proximal insertion is more compliant (more elastic), then the tendon will be what yields to the stretch. Not the stiff muscle! Consider in injury repair that you may not actually be stretching what you think you are stretching.

In yoga therapy we really care about alignment in poses. Good alignment means targeting stiff tissues that do not readily yield, and avoiding overstretching tissues that are already weak.

We must avoid lots of aggressive stretching in an attempt to increase range, or a tendon injury may occur. The best way to prevent injury is to strengthen your tendons through progressive adaptation. This means resistance training. When we correctly load the muscle with resistance then we will load the tendons, and the best news is that eventually the tensile strength will increase.

Resistance stretching is unlike standard stretching, which extends a muscle and then tries to relax it at its longest point, resistance stretching starts the muscle at its shortest point and draws it to its longest point, all the while using the person’s own body to resist the stretch. This allows the muscle to both contract and lengthen at the same time, improving both flexibility and strength. Proponents of resistance stretching claim that by contracting the muscle at the same time as it is lengthened, the muscle is allowed to truly stretch and strengthen itself.

To stretch exactly the muscle that you want to be stretching and not your possibly injured tendons, it is good to use yoga props, blocks, belts, bolsters with the guidance of a yoga therapist. This helps to fully direct the stretch. Using your own body weight is also wonderful (and very “good” yoga). Partner assisted stretching through private yoga therapy sessions is another successful method of directing the stretch to where it needs to be.

Passive stretching in yoga practice is still useful. Do not throw the baby out with the bath water! Restorative yoga targets the nervous system, upregulating the parasympathetic response and downregulating neuromuscular activity. Restorative yoga with correct prop placement is beneficial, as it does help muscles relax. It also helps develop the mind body connection and proprioception, enhancing our neural sensitivity and mindful connection to what is going on in our muscles.

Whatever you do, you would be wise to consider creating strength and optimal muscle function at any new range of motion that you create for yourself. Do try and avoid creating a hypermobile body more subject to injury, nerve damage and connective tissue injury. The main point is to not just stay focused on stretching for flexibility, but look more at stretching for function and performance, which must involve neuromuscular activity.