Stretching – Why is it So Important?

Why is it that regular Yoga participants (‘yogi’) always look so relaxed and pain-free?

Is it because they’ve achieved a zen state of cosmic, inner calmness? Or could it be that their muscles aren’t locked in semi-permanent contraction, pulling joints out of place, and creating a myriad of aches and pains?

My money is on a lack of aches and pains and the ability to move freely.

Aches and pains tend to accumulate as we adapt to the modern lifestyle where we are plagued by increasingly sedentary jobs and a lack of time for ‘non-urgent’ activities such as…stretching.

As I’ve adapted to a desk job, I’ve noticed that amongst other things my:

• lower back aches
• upper back has become rounded, and my chest tight as the screen ‘sucks me in’
• hip flexors and hamstrings have become short and tight as they accommodate life in a chair.

Add to that, years of half-hearted rehabilitation from the odd sporting injury and my movement is anything but ‘free’.

Mentally, I feel like I could run 100m as fast as ever. In reality, when I need to accelerate to avoid oncoming traffic whilst crossing the road, all that eventuates is a weird, shuffling hobble.

You see, my movement at key joints is restricted. Rather than my muscles being long and strong, many are short and tight while others are long and weak. This sad state of affairs is due to a significant loss of flexibility. For too many years I’ve neglected an obvious need to stretch.

Stretching is essential. We pay the price when we take it for granted.

So, in this article we’ll look at:

• Why flexibility is important
• What happens physiologically when we stretch
• When to stretch and at what intensity
• Maximising effectiveness via assisted stretching

Why is flexibility important?

‘Flexibility’ is one of the nine fundamental fitness components we cover in our Personal Training programme. It refers to the ability of joints and muscles to move through their full range without restriction or pain.

Ultimately, we stretch in order to improve and maintain our flexibility. There are some more specific benefits however, which include:

• Improved health and reduced stress
• Reduced aches and pains
• Improved movement
• Reduced injury risk
• Minimised wear and tear on joints
• The ability to produce more force for longer.

When muscles lose flexibility, they become shorter and tighter than normal. This makes them more vulnerable to injury in the form of muscle tears. Additionally, short, tight muscles can pull body parts out of their natural alignment. This results in loads being unevenly distributed through the joints, leading to aches, pains, injury, and premature joint deterioration.

Our ability to move freely and effectively is hindered by a lack of flexibility. For example, my ability to jump during a game of social rugby is limited by short, tight muscles in my legs – less range of movement equals less opportunity for the contractile elements in those muscles to generate the force required to get me off the ground.

As our understanding of the mind-body connection improves, the connection between physical and mental tension becomes more obvious. Tight muscles are tense muscles as they become locked in a state of semi-permanent contraction. Constant tension, whether physical or mental, is draining. By relieving muscle tension, stretching helps to improve health by reducing overall stress.

Now the good thing is, you don’t need to become a yogi to receive the benefits of enhanced flexibility. You just need to stretch, regularly and correctly, and occasionally with a bit of help!

What happens physiologically when we stretch?

Stretching is ‘neuro-muscular’; its success relies on the effective interaction of the nervous and muscular systems.

To understand how stretching ‘works’ we need to develop an understanding of ‘muscle spindles’ and the ‘myotatic stretch reflex’ [ref 1]. ‘Myotatic’ simply means ‘related to or involved in a muscular stretch reflex’.

Muscle spindles link the nervous and muscular systems. They are specialised sensory receptors located within the belly of skeletal muscles which detect changes in muscle length, and the speed of those changes.

Once changes have been detected, the spindles send this information to the spinal cord via ‘afferent’ sensory neurons (nerves). This information triggers the virtually instantaneous stretch reflex.

The stretch reflex results in information being sent back from the spinal cord to the muscle via ‘efferent’ motor neurons (nerves). This information tells the stretched muscle to contract in order to resist the changes in muscle length. The faster and greater the detected change in muscle length, the stronger the reflex response will be.

The stretch reflex is inherently protective. Its purpose is to prevent injury. For example, if I’m walking down the road and accidentally step into a pothole and roll my ankle, the stretch reflex will trigger and protect me from serious injury. It does this by causing the stretched muscles to contract and resist the stretch that was rapidly foisted on the muscle and its tendon by the pothole.

Without this reflex, a broken ankle is a likely outcome. With the reflex, a minor sprain is probably the worst outcome I could expect.

But how does this all relate to stretching?

The stretch reflex needs to be calmed down!

Effective stretching of muscles requires this reflex to be ‘calmed down’. When an initial position of ‘stretch’ is held for a prolonged period of time, the signalling from the muscle spindle starts to diminish. This results in the reflex response calming down; the nervous system learns that there isn’t any danger that needs a protective response.

Consequently, the muscle relaxes. At this point it can be moved into a position of greater ‘stretch’. This is why you’ve been told to hold stretches for ‘X’ number of seconds.

Perhaps you’ve noticed this yourself; after 5-10 seconds of a stretch, the stretched muscle starts to relax (as the reflex response calms down). At this point, you can take the stretch a little further and start to really gain the benefits of ‘stretching’.

What intensity should stretches be held at?

To be effective, stretches should be taken to and held it at a position where they are felt as ‘moderate-strong’, but never painful.

When working with clients, we recommend using the RPE Scale (Rating of Perceived Exertion). Once this scale is understood, it allows the person stretching (or being stretched) to identify their ideal intensity.

To be most effective, stretches should be held at an RPE of 6-7/10.

Initially, this means you’d take the stretch to a point where it’s intensity is perceived to be 6-7/10. As the stretch reflex diminishes, the perceived intensity of the stretch will drop accordingly. As this happens, the stretch should be progressed to bring it’s intensity back up to 6-7/10. At this point it should be held again.

*NB. This section on intensity applies to stretches that are held for a period of time. However, not all stretches are held, as we’re about to find out.

When should we stretch?

From an exercise perspective, we recommend stretching at the start and end of every workout. The types of stretching used should be quite different though. Once again, this relates to the stretch reflex.

Because the stretch reflex is protective and produces tension, we can benefit from it during a workout. For example, if I’m planning on doing some explosive activities during my workout, the tension produced by the stretch reflex helps me generate force.

The more force I can produce, the better my explosive performance will be.

And if I’m training at high-intensity, I certainly want my protective reflexes on full alert – just in case something goes wrong.

(Source: ACC SportSmart)

Prior to a workout we engage in ‘dynamic stretching’. This involves activities such as arm and leg swings, the walking calf stretch (above), or unloaded repetitions of the exercises to follow. Dynamic stretching doesn’t involve holding stretches for a prolonged period of time. Hence it doesn’t dial the stretch reflex down.

Dynamic stretching serves to prepare muscles and joints to work effectively within their current range.

At the end of a workout, we engage in ‘static stretching’ to improve flexibility by extending muscle and joint range. This also aids recovery by:

• Returning the muscle-tendon complex to a more relaxed state (or tone)
• Restricting blood flow (during the stretch) and then re-introducing blood flow as we relax after the stretch.

Static stretching involves holding positions of stretch for prolonged periods (15-60 seconds). This enables the stretch reflex to ‘calm down’.

Once calmed, the muscle relaxes somewhat which enables the stretch to be progressed (taken further and held for longer). It’s this progression that increases flexibility. That is, as long as such stretching is completed frequently and included in every workout!

How can we maximise the effectiveness of stretching?

Dynamic and static stretching can be great for improving and maintaining flexibility. There are limits to these forms of stretching though.

On one’s own, such stretching can become somewhat tedious, and therefore easy to ‘forget’. Additionally, stretches for some muscles can be awkward, or hard to attain and hold at the requisite intensity.

In the elective courses for our Personal Trainer programme, we teach an advanced form of stretching known as Assisted Stretching.

Assisted stretching employs several different techniques which produce dramatic and rapid improvements in flexibility. For safety and effectiveness, they are performed with the assistance of a person experienced in this form of stretching. Hence the title ‘Assisted Stretching’.

The most basic assisted stretching technique is the ‘contract-relax’ (CR) technique.

Here, the target muscle is moved into its initial position of stretch and held. Following this, the person being ‘stretched’ is instructed to contract the target muscle as hard as they can, against resistance provided by the ‘stretcher’. The stretcher doesn’t allow any movement to occur, hence the contraction is ‘isometric’ (without movement).

When this resisted contraction is sustained for a short period (5-6 seconds) a response known as ‘autogenic inhibition’ occurs; sensory receptors in the tendons of the stretched (and isometrically contracted) muscle reduce their protective firing, enabling the muscle to relax further.

Following this contraction, the stretch is progressed further still and held at the requisite intensity of 6-7/10. This contract-relax cycle (it should really be ‘stretch-contract-relax-stretch’) is repeated 2-4 times depending on the clients comfort, improvements in flexibility and time availability.

Another technique we teach is ‘CRAC’ stretching. This is similar to the CR techniques; it adds the contraction of opposing muscle groups (antagonists) to manipulate the bodies neuro-muscular responses even further, for even greater effect.

A final word

Of all the fitness components, flexibility is the one we tend to attach the least value to. Most of us prioritise getting stronger, faster, fitter, bigger, or leaner.

Few of us prioritise getting more flexible…until our lack of flexibility becomes a problem.

Don’t be like me and wait until accumulated aches, pains and movement dysfunction forces you to stretch frequently.

Learn how to stretch correctly and incorporate regular stretching into your exercise regime. And if you’re interested in helping others to dramatically improve their flexibility, study Personal Training with us and learn how to apply Assisted Stretching.

References

1. Bhattacharyya, K. (2017). The stretch reflex and the contributions of C David Marsden. Annals of the Indian Academy of Neurology. https://doi.org/10.4103/0972-2327.199906