Strap on your seatbelts for this one, folks. It could get hairy.
Because this post is made for an evidence-based discussion, I am going to remain as objective as I possibly can and also provide arguments for both sides of this debate.
I will cover whether stretching:
- Improves posture
- Reduces pain
- Improves performance
- Potential alternative methods
TL;DR: The evidence is very shaky on whether stretching works as we originally thought. It is relatively clear that while it can help alleviate pain & improve flexibility in the short-term, long-term effects are inconsistent. Static stretching also does not appear to meaningfully improve posture and it also hampers performance when taken too far. Dynamic stretching can have a place in a dynamic warm-up.
What happens when we stretch?
Most people stretch to “lengthen” tissues, but that’s actually probably not what’s going on underneath the surface.
Does Stretching Improve Posture?
Because we know that posture has little to do with actual pain (Laird et. al, 2016; Grundy & Roberts, 1984 to name a few), this one can be tricky.
Having better overall posture can still help improve your overall muscle balance, body language, and perceived health. Think of someone who has a huge hunchback versus someone who stands up straight – who would you correlate health with more?
It’s also difficult to answer this question because there is no one perfect definition of “good posture”. The medical community has yet to come to a consensus on that one, so it is up to the practitioner and individual to determine what that is.
That being said, a systematic review of postural correction studies in 2014 by Filho et. al found:
This review showed that for the acute effects of
stretching exercise aimed at correcting postural deviations,
there is still no consensus in the literature that supports
its effectiveness. As for the chronic effects, although
noticed a slight trend as to its benefits in postural
correction, literature, yet also presents little evidence
to support this assumption.
However, there are quite a few studies that add in the variable of strengthening exercises to stretching and they seem to find outcomes trending towards positive results:
- Stretching and strengthening exercises: their effect on three-dimensional scapular kinematics
- The Effects of Strengthening, Stretching and Comprehensive Exercises on Forward Shoulder Posture Correction
Is it the stretching or the strengthening making the difference? My guess would be towards the latter, but we are unsure.
Does Stretching Reduce Pain or Injuries?
As for pain reduction and injury prevention, it’s a bit more clear. However, there are still mixed signals being sent.
Many systematic reviews and high-quality studies have looked into whether stretching actually does reduce pain and prevent injuries:
|Comparisons of hamstring flexibility between individuals with and without low back pain: systematic review with meta-analysis||Very little correlation, authors could not come to conclusion|
|A Randomized Trial Comparing Yoga, Stretching, and a Self-care Book for Chronic Low Back Pain||Stretching classes > Yoga Classes > Self-Care book in terms of most positive results for pain relief|
|Stretching to reduce work-related musculoskeletal disorders: A systematic review||Studies were found to be relatively low-quality with mixed findings of both positive & negative outcomes|
|The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomized controlled trials||No correlation between stretching and injury prevention|
|A pragmatic randomized trial of stretching before and after physical activity to prevent injury and soreness||Stretching did not reduce most injury risk, but did for some muscles, ligaments, and tendons|
We can pretty confidently say it doesn’t meaningfully reduce injuries, but many people do claim it feels good and that can be important. If it makes them feel better, even if there’s nothing meaningfully truly happening (we don’t know for sure), then that is worth something.
Does Stretching Improve Performance?
As always, context is king here. Warm-ups have been proven to provide insurance against injuries and over-use injuries (Soligard, et. al, 2008), but most warm-ups have a combination of static and dynamic drills. They also frequently have “muscle activating” (whatever that means) drills.
We also can say confidently that stretching does not improve performance as it relates to jumping, running, or force production (Shrier, 2004).
I think many people are also familiar with the (relatively) recent idea that longer-duration static stretching can actually decrease performance due to the over-lengthening of muscles, leading to decreased stiffness and therefore less force production (Islamoglu et. al, 2016).
However, dynamic stretching does seem to have an appropriate place in a warm-up setting to increase body temperature and prepare the tissues to go through an increased range of motion (Opplert & Babault, 2017).
Alternatives to Stretching?
Fair warning: This is when I get into my own opinion.
I think everything has it’s place. Stretching has worked for many people and we can’t discredit that, however I believe that it’s important to remain open-minded and consider potential alternatives.
I think people who don’t get the results they want to from stretching continue to do so because they simply don’t know an alternative.
I personally believe we should consider the role of the antagonist (opposing muscle usually on the other side) musculature involved in the muscle we want to stretch.
For example, if someone has Anterior Pelvic Tilt, they probably have tight hip flexors and feel the need to stretch them. This usually comes with hamstrings that might feel tight too, but those hamstrings aren’t tight because they’re short, they’re likely tight because they’re long and already tense/stretched. Imagine a rope being pulled from both ends.
Therefore, if we understood the underlying cause (pelvis position) and activated the antagonists of the hip flexors (hamstrings & obliques), we might able to both “stretch” the muscle out but also activate the opposing muscle to help the stretch “stick” a little better.
Here is an exercise that can do that.
This approach is just my own view and not one that should be adopted without considering the evidence. In all likelihood, it is important to consider a combination of several different interventions to get the outcome you want.