6 Stretching Myths - Busted!

The practice of stretching out your muscles before, during and after your workouts has been commonplace as long as anyone can remember. In fact some fitness enthusiasts practice it religiously but is stretching really doing us any good and is it really having the effect on our bodies that we intend it to have?

When we take a look at the scientific research on the topic of stretching, we discover that stretching is not all it has been cracked up to be. In fact, stretching may even be doing us more "harm" than good.

Let's take a look at the 6 main reasons why people stretch and see what the research has to say...

Stretching Myth No. 1:

Stretching Increases Range of Motion in People with Limited Mobility due to Chronically Tight Muscles (Contractures).

People have always thought of muscles as stretchy things like elastic bands, when in fact the architecture of muscle is more like that of Velcro in that the individual segments of the muscle "unhook" and "re-hook" further along the line resulting in an increase in overall length. Although there are very small elastic components within the muscle architecture, for the most part, muscle does not stretch as most people seem to think it does. One of the main reasons people stretch is to increase joint range of motion (ROM). Although there will be an increase in ROM after a bout of stretching due to the stretch causing a relaxation in the muscle (autogenic inhibition), this effect is only temporary. The research shows us that stretching does not have clinically important effects on joint mobility in people with, or at risk of, chronically tight muscles (contractures)[1].

Stretching Myth No. 2:

Stretching Before/After Exercise Reduces Muscle Soreness.

It is commonly believed that stretching will help to reduce post exercise muscle soreness also known as delayed onset muscle soreness (DOMS). Any positive associations are likely due to the placebo effect and are entirely anecdotal, since solid research found no significant reductions in DOMS by stretching before/after exercise[2].

Stretching Myth No. 3:

Stretching Helps to Prevent Injuries.

The second reason why people stretch is because they believe that it will reduce their risk of a muscle strain or otherwise getting injured. There is absolutely no evidence to support this idea. A meta analysis of 60 different randomized control trials did however show that stretching had no benefit to injury prevention what so ever[3]. In fact, stretching before or during exercise could put you at a higher risk of injury due to the temporary reductions in muscle performance that result after stretching (remember autogenic inhibition mentioned above). One study demonstrated that after stretching, muscle peak force decreased significantly (by 54%) and remained depressed for the entire recovery period (2 hours)[4]. Put simply, stretching makes you weak - the opposite to what you're likely trying to achieve with your workouts.

Stretching Myth No. 4:

Stretching Improves Sporting Performance.

Contrary to popular belief, stretching has quite the opposite affect to improving physical performance. As we learnt after busting Myth No.3, stretching makes your muscles weak so it's nonsensical to think that weak muscles would result in an improvement in performance. Reassuringly the evidence supports this logic. One study showed how a 60 second stretch before a vertical jump test reduced performance (jump height) by 3.4%[5]. Another study showed that static stretching before running slowed down the initial 100m pace and jump height was reduced by over 9%[6]. If your goals are muscle growth then stretching is disastrous for your "gainz" since performing flexibility training immediately before resistance training can contribute to a lower number of repetitions, total volume, and reduced muscle hypertrophy[7]. The bottom line is, if your goals are to improve your strength and performance, leave the stretching for the yogis, professional gymnasts and ballet dancers.

Stretching Myth No. 5:

Stretching Muscles Can Result in a Permanent Change in the Resting Muscle's Length.

As explained earlier, muscles don't stretch they lengthen; you lengthen a leather belt by changing the notch position, not by trying to stretch the leather. So once you understand the anatomy of the muscle, it's nonsensical to think that you can elicit a permanent change in muscle length by stretching it - if you could, you'd be flopping around everywhere like Mr. Fantastic! Research shows that after 6 weeks of static stretching, no structural change in muscle length was detected despite a significant increase in range of motion which can only be explained as being a change in tolerance to the stretch[8]. In other words, you just get used to the pain and can push the position a little bit further each time.

Then there's fascia - The idea of stretching fascia (think Iliotibial Band stretches) becomes even more silly when you learn that fascia has the tensile strength of steel - ever tried to stretch steel? Not surprisingly, this study showed no structural change in fiscal length after stretching[9]. Besides, fascia isn't supposed to be loose, if it was it wouldn't serve its intended purpose - to be tight.

Stretching Myth No. 6:

Stretching Helps to Tone Your Muscles

It's a common belief that stretching will make your muscles long, lean and toned. As we've already established in Myth No.5, stretching does not change the resting length of muscles so it is impossible that stretching will make your muscles longer. Neither does stretching "tone" your muscles. In fact stretching before your workouts can result in suboptimal muscle tone development by way of reducing the number of repetitions and total volume you're able to complete[7].

Muscle Tightness is Secondary to Muscle Weakness:

Muscles become tight when the opposing muscles are weak/inhibited. The tightness is being generated by your nervous system as a form of protection to purposefully prevent you from going into a position of instability where you're likely to get injured. As far as your body is concerned, "Mobility Without Stability = Vulnerability!"

The tightness is a symptom of weakness elsewhere, not the cause. Using stretching (or any other form of intervention that loosens the tightness) is effectively violating your body's own protective mechanism and does nothing to address the weakness/instability that caused it. Remember, "Mobility Without Stability = Vulnerability!"

So if stretching is not the answer to increasing flexibility, what is?

If you need to increase your range of motion, instead of trying to stretch the tight muscles, work on activating and strengthening the muscles responsible for getting you into the position you want to get in to. So for example, if your hamstrings are tight and you can't touch your toes, then do some isometric exercises for your hip flexors and abdominal muscles since these are the muscle required to contract properly to get you closer to your toes. Once these muscles are firing better, your body recognizes that it no longer needs to protect, so the tightness literally melts away from the hamstrings and your range of motion will improve. Keep those hip flexors and abdominals strong in their shortened position and you'll have achieved long term flexibility without the need to stretch the hamstrings any more.

The Bottom Line: 

Stretching may increase mobility/flexibility by temporarily inhibiting the tight muscles but it does nothing for long term flexibility or improving strength and stability in that new range you've just opened up. Instead of stretching, use isometric exercises to activate the opposing muscles.

Click here to learn more about muscle activation techniques.

References:

[1] Katalinic OM, Harvey LA, Herbert RD, Moseley AM, Lannin NA, Schurr K. Stretch for the treatment and prevention of contractures. Cochrane Database Syst Rev. 2010 Sep 8;(9):CD007455.

[2] Herbert RD, de Noronha M, Kamper SJ. Stretching to prevent or reduce muscle soreness after exercise. Cochrane Database Syst Rev. 2011 Jul 6;(7):CD004577.

[3] Leppänen M, Aaltonen S, Parkkari J, Heinonen A, Kujala UM Interventions to prevent sports related injuries: a systematic review and meta-analysis of randomised controlled trials. Sports Med. 2014 Apr;44(4):473-86.

[4] Esposito F, Limonta E, Cè E. Time course of stretching-induced changes in mechanomyogram and force characteristics. J Electromyogr Kinesiol. 2011 Oct;21(5):795-802.

[5] Pinto MD, Wilhelm EN, Tricoli V, Pinto RS, Blazevich AJ. Differential effects of 30- vs. 60-second static muscle stretching on vertical jump performance. J Strength Cond Res. 2014 Dec;28(12):3440-6.

[6] Damasceno MV, Duarte M, Pasqua LA, Lima-Silva AE, MacIntosh BR4, Bertuzzi R1. Static stretching alters neuromuscular function and pacing strategy, but not performance during a 3-km running time-trial. PLoS One. 2014 Jun 6;9(6):e99238.

[7] Junior RM, Berton R, de Souza TM, Chacon-Mikahil MP, Cavaglieri CR. Effect of the flexibility training performed immediately before resistance training on muscle hypertrophy, maximum strength and flexibility. Eur J Appl Physiol. 2017 Apr;117(4):767-774.

[8] Konrad A, Tilp M. Increased range of motion after static stretching is not due to changes in muscle and tendon structures. Clin Biomech (Bristol, Avon). 2014 Jun;29(6):636-42.