Stretching - the truth!

We’re told to stretch. We are given stretches at the gym, we go to yoga classes, we subscribe to ROMWOD… 

Then we hear from another source not to stretch, but to roll out and mobilise instead.

Or maybe we’ve even heard not to bother with mobility work at all, because it doesn’t seem to have any bearing on athletic performance.

So, what do you do? Should you stretch?

Okay, the simple answer is: yes, stretching is a good thing to do.

Why? Because it increases your functional range of movement. 

I know, I know, these days as soon as someone wants to sound legitimate in the movement field, they throw the word “functional” into every second sentence. But in this article I mean it in the clinical sense. 

Let’s get technical for a little bit. Your “range of movement” with regards to any specific joint is literally how far you can move it. For example, your ability to touch your toes (or not) demonstrates the range of movement in your hip joints and spine, as well as the length of your hamstrings. Range of movement can be limited by tight muscles, tight ligaments, or sometimes the shape of the bones that make up the joint. 

There is a difference, however, between how far a given joint can move when you are relaxed, and the joint is being moved for you (for example, when you are lying on your back and someone is stretching one of your hamstrings for you), and how far you can move it yourself (for example, when you are standing upright and you lift your leg straight out in front of you). This second example refers to your “functional” range of movement.

Functional range of movement: how far you can move a given joint when actively moving the joint and your body yourself.

The distinction is important because your ability to effectively use the entire range of your movement can make a big difference to how you move, and could effect things like athletic performance and the chance of future injury. (What I mean is there have been some studies that show that injury rates fall in a population of people who stretch regularly, but there have also been studies that DON’T support this. Please note: I’m NOT saying that if you stretch regularly you will never get injured or feel pain!) There have also been a number of studies that show that regular stretching as a part of an overall exercise program helps recovery from orthopaedic injuries, and is beneficial for anyone over 60.

So, we’ve established that it’s good to stretch. It’s not that simple, however.

How you stretch matters. 

Three main categories of stretching: static, dynamic, and pre-contraction stretching. Which you perform and when makes a difference.

Static stretching: this is the most commonly practiced form of stretching. Static stretching is when you find an hold a stretch without moving for a period of time, either actively (you do it yourself) or passively (for example, someone else does it for you). The research suggests that the best amount of time to hold a stretch is between 15 and 30 seconds, between 2-4 times. Continuing to stretch beyond that apparently holds no benefit for the average person that has been measured in a range of studies. Those over 60 years of age may benefit from holding a stretch for up to 60 seconds and some studies suggest that static stretching is more effective than other types of stretching for the same people. Some people like to hold a stretch for longer (sometimes much longer). While the evidence suggests this brings no further benefit, if you like to do so, it probably doesn't hurt either, so go for it.

Dynamic stretching: this is where the joint is actively and repeatedly taken to it’s end range. This can be done actively, or ballistically (which involves more rapid, “bouncing” movement at end range). Ballistic stretching is associated with a greater risk of injury, so it is not recommended. Active stretching, however, can be very effective.

Pre-contraction stretching: this involves contracting a muscle immediately before stretching. The muscle contracted is either the one you intend to stretch, or the antagonist (the opposite muscle, for example, if you were stretching the hamstring, you may contract the hip flexors prior to the stretch). There are a variety of different techniques, including PNF (proprioceptive neuromuscular facilitation), PIR (post isometric relaxation), and PFS (post-facilitation stretch). Try holding a strong contraction of the muscle you want to stretch for 5 to 10 seconds, then relax and move into the stretch for a 15 second hold, and repeat several times.

Here’s the important stuff about these different types of stretches: while all have been shown to increase your functional range of movement, it looks like static stretching may decrease your power output and therefore your athletic performance if conducted immediately before competing or training. Dynamic and pre-contraction stretching don’t have the same effect, however, and in some studies even seem to improve performance.

What does that mean? When structuring a warm-up, include active or pre-contraction stretches. Save the static stretches for another time.

This doesn’t mean you should never include static stretching in your routine. It can still be very beneficial in terms of maintaining a good functional range of motion. And there may be other benefits, including relaxation and stress reduction. Just be discerning about how and when you stretch. Using various mobilisation techniques like foam rolling in addition to stretching can also be worthwhile. (More about that another time…)

Another important point is that different types of stretching seem more effective for different people, and there isn’t necessarily any clear way to determine what will work for you except to try them out. Be prepared to structure your individual mobility program to suit what gets you the best results.

Now, if all you wanted was what to do and when to do it, you may choose to stop reading now. If, like me, you like all the nerdy info about how and why things in your body work, below is a brief attempt to explain where the current thinking about stretching sits.

There have been a range of theories to account for the increase in range of movement that occurs with stretching. 

  1. Lengthening contractile units: One theory is that stretching lengthens the actual contractile units within muscles. These units are called sarcomeres, and are made up of two types of protein molecules called myosin and actin. These molecules are very long, and occur in pairs. The myosin can attach to actin and through a series of specific chemical reactions involving calcium, ATP and magnesium, ratchet itself along. This causes the sarcomere to shorten, which is the basis for muscle contraction. At one time the primary theory to explain the increase in range of motion from stretching was that the body responded to stretching by increasing the length of the myosin and actin molecules, meaning that at rest the sarcomere was actually longer. 
  2. Lengthening fascia: Another theory relates to the connective tissue surrounding muscle. All organs in the body including muscles sit within a matrix of connective tissue or fascia, that helps support these organs and connect them to the surrounding body. The fascia is not able to contract like sarcomeres, but some forms of connective tissue can be elastic to allow for movement of the underlying organ. There has been speculation that stretching alters the structure of the fascia, allowing it to lengthen more under force, and that this accounts for the lengthening of muscle with stretching.
  3. Neurological changes: The current best theory is that stretching doesn’t actually introduce any structural change to the muscle or connective tissue. Rather, it alters the brain’s perception of discomfort or pain at the end-ranges of movement. We know that pain can cause inhibition of muscle activation, so reducing perceived pain at the end range allows you to more effectively contract your muscles throughout the full range of your movement. The thinking is that this is why it increases functional range of movement.

So there you have it. I hope this information helps you understand stretching, and where it can fit into your overall exercise routine. I intend to write about mobilising such as foam rolling too, but I thought trying to fit that into this article would be a bit of a stretch…

Please note: this article does not constitute recommendations for the treatment of any injuries, and is not a substitute for the accurate diagnosis and treatment of any such injuries.