When researchers began to show that stretching isn’t as great as once thought, the knee-jerk reaction from the health and fitness community (or should we say: industry) was:
“well… obviously it’s because people are stretching wrong!”
This spawned tons of magazine and website articles from ‘gurus’ who proclaimed that the ‘right’ way to stretch wasn’t ‘static’ stretching, but ‘dynamic’ or ‘active’ stretching.
But are these other methods really any better?
In Part I we reviewed the different types of stretching.
In Part II, we’ll review what the research is telling us so far. Finally, we’ll outline some recommendations you can start using NOW to take advantage of the ‘pros’, while avoiding the ‘cons’!
For a review on the pros and cons of stretching, read: Stretching. In summary:
1. stretching does improve flexibility,
2. does not improve athletic performance,
3. does not prevent injuries, and
4. stretching can even temporarily reduce strength.
Most of that research has been done on ‘static’ stretching.
But are different ‘types’ any better?
For those interested in detail, let’s look at the research:
For the goal of improving range of motion, research results are mixed. In many cases, results favor typically ‘Passive-Static’ stretching for improving range of motion 1, 2, 3, 4, 5, 6. Still, a few studies do favor active methods 7, 8. Effect sizes huh? almost always look small, meaning the differences are never that big in any of the studies. Based on this review, the overall difference between methods isn’t much to get excited about!
Bottom line: other types of stretching are not really any better!
In fact, classic static stretching might be the best way to improve flexibility.
But why not? If active/dynamic methods are more “functional” (meaning they mimic actual athletic performance more) then why aren’t they any better than plain old static stretching?
Here are some possible reasons for each type:
Active stretching: Active stretching may not actually cause much of a ‘stretch’. Even if a muscle is strong enough to lift a limb all the way (to stretch the opposite muscle), it can still be limited by other factors. Muscles can only contract (shorten) so much, and once they bunch up, they can’t go any further. Then there is ‘active insufficiency’ which means once a muscle is shortened so far at one joint, it can’t produce enough force to shorten all the way at another joint here’s an example. It’s possible to reach this point in the agonist (contracting muscles) before a good stretch is obtained in the antagonist (opposite muscle).
Dynamic stretching: Flexibility is more of a neurological adaptation: flexibility seems to increase because people tolerate stretching better… not because the muscle actually gets longer or more extensible 9. Since dynamic stretches are constantly moving, they probably don’t allow for enough time in the ‘stretched’ position (the end range of motion) to allow for much of an adaptation. Same issue with ballistic stretching: and research backs this: a study found static stretching improves range of motion better than ballistic 10.
PNF stretching: This kind of stretching works by temporarily decreasing the normal reflexive tightening of your muscles when they detect a stretch. But if increasing flexibility is a matter of improving your ‘stretch tolerance’, than is this just making it easier to tolerate at the moment, but no better in the long run? This may be similar to how NSAID’s work to decrease muscle soreness, but can harm exercise gains because the inflammation is key for muscle repair. Bottom line: making things easier usually doesn’t help. It’s supposed to be a bit uncomfortable. It’s supposed to be difficult. No short cuts!
Static stretching: Seems best for improving range of motion. This is because you actually hold the end range for a period of time… a good idea if what you are trying to do is improve your ‘stretch tolerance’.
But no one ever said stretching didn’t work. It’s been known for ages to be good for improving flexibility. The problem was with athletic performance and injury prevention.
So what about those things?
Let’s move on!
For athletic performance, however, dynamic stretching may actually help! Using dynamic stretching as part of a warm up seems to improve sports performance 11, improve agility 12, and improve muscular power 13,14.
This actually makes some sense. Dynamic stretching looks more like a warm up than an actual stretch. And we already knew warm-ups are helpful for sports performance, and possibly for preventing injuries.
Furthermore, it may be exactly how we should be warming up. Dynamic stretching even seems to be better than a simple jog 15, as it brings you through your full range of motion in a variety of movements. The key is to cover as much range as possible, in many different ways, preferably using movements similar to the activity you are warming up for.
It should be emphasized that it is dynamic stretching, not the other types, for which these results were found. Dynamic stretching is almost always ‘active’, not ‘passive’.
Okay, that’s cool! So what about injuries?
Finally, the biggest problem of all:
Lack of flexibility is not why injuries happen…
Muscles tend to get injured during eccentric contractions (like lowering a weight instead of picking it up) within a muscles normal range of motion 16. You’re more likely to hurt yourself with a big forceful movement or a quick switch in direction. The reason ‘over-extending’ yourself can cause strains is the same: the tremendous force this imparts on the muscle while it eccentrically contracts to resist. If no muscles were active, you would probably get a ligament sprain rather than a muscle strain.
For more information on how most injuries happen, read: How Injuries Happen.
So it does not matter how someone stretches… flexibility isn’t the problem!
- For increasing flexibility, good old ‘static’ stretching seems to be the best. But because it temporarily decreases strength, stretch after exercise.
- For improving athletic performance, it seems a warm up with dynamic stretching might actually be helpful before exercise.
- For preventing injuries… no type of stretching will help. Just warm up, do things right, and be careful!
To take advantage of the ‘pros’ of stretching, while avoiding as many ‘cons’ as you can:
1. Warm-up (raise your temperature and sweat a little) and include simple, sport-specific, ‘dynamic’ stretches. ‘Static’ stretches should be limited to 15-30 second holds, once per position. Warm-up for 10-15 minutes, or until you feel ready to rock.
2. Exercise / Compete / Perform / Practice… do your thing!
3. Lots of ‘Static’ stretching afterwards to improve flexibility, if you need to. Hold sport specific positions at the end range (avoid pain) for about a minute, repeating 2-3 times.
Next article about stretching will FINALLY be a HOW-TO article.
Hope this information cleared up a LOT of confusion.