Stretching Before Exercising Weakens Muscles

Khemisty writes "Back in grade school you were probably taught the importance of warm-up exercises, and it's likely you've continued with pretty much the same routine ever since. Science, however, has moved on. Researchers now believe that some of the more entrenched elements of many athletes' warm-up regimens are not only a waste of time but are actually bad for you. The old presumption that holding a stretch for 20 to 30 seconds — known as static stretching — primes muscles for a workout is dead wrong. It actually weakens them. In a recent study conducted at the University of Nevada, athletes generated less force from their leg muscles after static stretching than they did after not stretching at all. Other studies have found that this stretching decreases muscle strength by as much as 30 percent. Also, stretching one leg's muscles can reduce strength in the other leg as well, probably because the central nervous system rebels against the movements."

Comments

Importance of warm-up

[moro_666]

Back in the days when i was in school, warm-ups were there to avoid injuries, not to increase your performance.

By making your muscles weaker, the chance to get an injury decreases as well. People have proved over time (and quite many times) that you are able to hurt yourself with the strength of your muscles alone (ever seen those 100m sprinters falling like bricks on half way ?).

Re:Importance of warm-up

[Registered Coward v2]

Back in the days when i was in school, warm-ups were there to avoid injuries, not to increase your performance.

By making your muscles weaker, the chance to get an injury decreases as well. People have proved over time (and quite many times) that you are able to hurt yourself with the strength of your muscles alone (ever seen those 100m sprinters falling like bricks on half way ?).

From the article:

THE RIGHT WARM-UP should do two things: loosen muscles and tendons to increase the range of motion of various joints, and literally warm up the body. When youâ(TM)re at rest, thereâ(TM)s less blood flow to muscles and tendons, and they stiffen. âoeYou need to make tissues and tendons compliant before beginning exercise,â Knudson says.

Re:Importance of warm-up

[Chees0rz]

I have been practicing this methodology for a while now. My highschool and college track coaches (and the assistants coming in) have preached Dynamic stretching (stretching through movement). So you do things like skipping, leg swings, high knee running, and a whole bunch of crazy things. It gets the muscles ready to move- not increase flexibility.


Increasing flexibility is for after the workout, where you hold a stretch for 20-30 seconds (for muscle memory).
Maybe I have drank too much of the koolaid, but I assume this is what the article is talking about. It's been around for a while (at least 8 years).

Re:Importance of warm-up

[Iberian]

In weight lifting you do not want to stretch your muscles out. In anything more aerobic you want to do light stretching and at the end of both you want to completely stretch your muscles.

Your muscles are able to put forth the most when they are not all stretched out similar to an elastic band. If you stretch it out several times it starts to lose its ability to snap back as quickly. For aerobic exercise though you don't want your muscles to cramp up which they have an increased chance of doing because of the nature of the exercise and the fact you are using it consistently over a long period of time.

No muscle works well though when it is damaged so if you try to rapidly stretch it by running or jumping hard while cold you just earned yourself a pulled hammy. Weightlifting though is different and once you get into it and start lifting heavy there are not many who stretch much at all before lifting. Maybe a quick set of low weight to get warm and make sure the muscles are ready for the range of motion and demand you are about to put on them.

Lame jokes aside go to the gym and you will see this was already well known before this study.

Re:Importance of warm-up

[fyngyrz]

The 30 second stretches are for after your workout, during the "cooling off" period.

That may be adequate for running, but it won't do for regimens with extreme range of motion, such as martial arts. We stretch for half an hour prior to a workout punctuated with short one-minute warm-ups every five minutes or so, and it definitely reduces injuries (which, as the GP has it, is the intent... not for "strength"... in fact, I've never heard — anywhere — that the act of stretching increases strength for the immediately succeeding session of exercise. I've been teaching martial arts for over twenty years.)

I can also tell you that if your body isn't prepared to reach an extended position, and it has to go there, either because you forced it to or someone else did, you had better have stretched first and be warmed up.

As for this line in TFS: "The old presumption that holding a stretch for 20 to 30 seconds -- known as static stretching -- primes muscles for a workout is dead wrong. It actually weakens them", the science of this has been known for many years. What happens is that the working elements of the muscle fibers are laid against each other in pairs with an intervening layer between; the more overlap, the more power can be generated because the overlapping surface area of the layer between is where the work gets done. When fibers are stretched, there is less overlap, hence the muscle can generate less power, but the muscle is longer.

Think of your forearm extended, and look at your bicep... see how it is long? Lots of fiber layers have slid against each other and now have considerably less overlap. Now move your arm to the 90 degree position at the elbow, and look at your bicep; it's bunched up, even if it isn't tense: many fiber layers are now slid to an overlapping position.

The number of fibers involved is the factor that determines the total amount of strength in your motion; high recruitment of fibers results in a strong motion, low recruitment results in a weak motion. We train to develop the ability to generate high recruitment on demand. But no matter the recruitment, if you start from a highly non-overlapped position, eg a stretched one, you'll generate less power with the stretched muscle.

This is the basis for moves like arm locks; if the arm is extended, not only is the leverage at the joint reduced, making it more difficult to close the arm against the lock, but the muscle is extended by the lock so that fiber overlap is minimal, which reduces the amount of force that can be generated by the muscle — it is literally a "double-whammy", and accounts for why a fully executed lock is so hard to exit using direct force (correct exits involve rotation of the arm or the lock itself in order to effect closure of the joint, and a good lock prevents such rotation.)

For any motion, you typically will have two muscle groups involved; the agonist, which is the muscle doing the work, and an antagonist, which is the muscle that would be responsible to reverse the motion. In the case of bending at the elbow, to close the arm, the bicep is the agonist and the triceps is the antagonist. If you are trying to open your arm, that is, extend your forearm, then the roles are reversed: The triceps is the agonist and the bicep is the antagonist. One of the key elements of controlling the force your body can generate is learning to really relax the antagonist, and again, stretching helps by teaching you what a really relaxed and extended muscle feels like; it is difficult to minimize fiber recruitment if you don't know what it feels like and the muscle isn't accustomed to that condition.

Anyway, my recommendation is that athletes ignore this report entirely; stretching significantly increases your range of motion, particularly in your ankles, legs, groin, waist, wrists, fingers, back, neck and shoulders, and to the degree that your sport requires (or risks) large range o

Re:Importance of warm-up

[Anonymous Coward]

I think this entire article is a load of attention seeking BS, and I will not believe a word of it until I see a proper peer-reviewed research paper in a medical journal that debunks stretching.

How about these:
Nelson AG, Kokkonen J, Arnall DA: Acute muscle stretching inhibits muscle strength endurance performance. J Strength Cond Res. 2005 May;19(2):338-43

Power K, Behm D, Cahill F, Carroll M, Young W: An acute bout of static stretching: effects on force and jumping performance. Med Sci Sports Exerc.2004 Aug;36(8):1389-96

Cramer JT, Housh TJ, Weir JP, Johnson GO, Coburn JW, Beck TW: The acute effects of static stretching on peak torque, mean power output, electromyography, and mechanomyography. Eur J Appl Physiol. 2005 Mar;93(5-6):530-9. Epub 2004 Dec 15

Fletcher IM, Jones B: The effect of different warm-up stretch protocols on 20 meter sprint performance in trained rugby union players. J Strength Cond Res. 2004 Nov;18(4):885-8

This is not exactly news. The studies have been showing these same results for years now.

Re:Importance of warm-up

[mopomi]

How could you possibly make your claim that

There is absolutely no evidence that stretching before exercise weakens muscles (note I used the exact same phrase as the title) so long as you don't over do it.

if you haven't actually read any peer-reviewed articles about it?! You do know about scholar.google.com, right? It's not that hard to check on the people interviewed in the NYTimes article. There are many papers on the subject. Yes, there is still work to be done to answer all the questions, but your ridiculous statement that there is absolutely no evidence that stretching (static) before exercise weakens muscles just shows that you haven't bothered to read about it.

Here's your spoon-fed google search with links to a few abstracts for your edification.

http://www.acsm-msse.org/pt/re/msse/abstract.00005768-200403000-00004.htm;jsessionid=JJgJGzgYVCy4qyLKzfW21kXYSGvYP3tWmM2WDyC6Nr1nvvvH7ykd!-1853705402!181195629!8091!-1

http://eric.ed.gov/ERICWebPortal/contentdelivery/servlet/ERICServlet?accno=ED448119 [PDF]

http://www.ncbi.nlm.nih.gov/pubmed/9368275

http://www.bmj.com/cgi/content/abridged/325/7362/468

http://www3.interscience.wiley.com/journal/119251161/abstract?CRETRY=1&SRETRY=0

http://www.cjsportsmed.com/pt/re/cjsm/abstract.00042752-200409000-00004.htm;jsessionid=JJgpcrQvSRyyCn1CG2XnW4WS6vzdsmrXnhG43kmLDT1CyhhCknr9!1600976923!181195628!8091!-1

http://apt.allenpress.com/perlserv/?request=get-abstract&doi=10.1519%2F1533-4287(2001)015%5B0098%3AAEOSAN%5D2.0.CO%3B2

Re:Importance of warm-up

[canadian_right]

You are wrong. A number of studies show that stretching when cold is not a good idea. As the article stated, stretching is good, AFTER, a light warm up like an easy jog for 5 to 10 minutes. Stretching when cold does not help prevent injury, and does not improve athletic performance. You should not do intense stretching before playing sports. If you need to improve flexibility do the stretching as a separate exercise on your work out days.

Stretch after warm up.
Stretch after your work-out, Athletes who stretch cold have more injuries.
Warm up, then stretch.
Stretching doesn't help beginners, too much bad for elite. (lots of pointers to articles/studies at end)
Fire Dept. says go easy on stretching, only after warm up.

I think that is enough for now. Only stretch after you warm up. Don't over do it.

Re:Importance of warm-up

[Anonymous Coward]

The effect of different warm-up stretch protocols on 20 meter sprint performance in trained rugby union players.

FYI: Some things you have been taught are wrong.

Re:Importance of warm-up

[ShadeOfBlue]

Actually, when they talk about the acute effects of stretching, they're talking about the immediate effects.

That is, weakened muscles are an acute effect because the effect only lasts ~30 minutes. Acute does not mean they stretched the bajeezus out of a muscle before the test.

Furthermore, you still seem to be having trouble grasping the difference between stretching, static stretching, and warming up.

Re:Importance of warm-up

[t0rkm3]

This study is actually a late-comer to the field. This sort of study has been out for more than a few years.

There are several tricks to this.

1. Dynamic warm-ups that result in a stretch can increase force production. Dynamic flexibility and static flexibility are related but not as linked as you may think.

2. Statically stretching the antagonist to intentionally weaken allow better performance esp on "simple" exercises with one or two predominant agonists. ie Bench press

3. This topic has been a discussion at the last 4 ACSM conferences. There are several studies that point to the existence of "stretch lag period" or "tendon slack" post static stretch. The quandary at this point is how long is the "slack" period. This is especially important for athletes that tend to have problems related to tendon length such as Patella-Femoral Pain Syndrome.

Re:Importance of warm-up

[Heymdall]

In semi-contact (kickboxing) class we're always instructed not to overstretch before the combat tournaments because that would slow us down. A warm-up is required but the stretching should be light. But as a result there are more injuries on the tournaments than on regular combat practices where we stretch a bit more.

Re:Importance of warm-up

[mopomi]

Actually, in 4x4 recovery, there's a strap called a "snatch-strap" used to pull stuck vehicles out of mud, etc. It's basically a bungee (with much less elasticity and much higher strength). You attach it to both vehicles, and the recovery vehicle gets a running start, pulls the snatch strap taught, stretching it in the process. The pulling vehicle eventually comes to a stop.

There's a bunch of energy stored in the snatch-strap, which wants to go back to its original shape. It eventually does return to its original shape, pulling either the stuck or unstuck vehicle toward the other (usually both toward a common "center"). As long as the frictional forces acting on the recovery vehicle are greater than those acting on the stuck vehicle, and the energy stored in the strap is high enough to overcome the forces acting on the stuck vehicle, the stuck vehicle will move.

This is used to avoid the dangerous situation of a cable suddenly and violently releasing its stored energy as it breaks. The snatch-strap deforms elastically while the cable deforms plastically and catastrophically.

But, yes, your analogy has some application to muscle strain. ;)

Performance vs. Health

[pete-classic]

Stretching might be bad for performance, but it does reduce injury. 30% more power in your legs is useless when you snap your achilles tendon. That happened to a coworker who didn't stretch before playing ultimate. They had to dig it out of his calf and re-attach it.

I'll stretch, thanks.

-Peter

Re:Performance vs. Health

[Timothy Brownawell]

Stretching might be bad for performance, but it does reduce injury.

From TFA:

Controversy remains about the extent to which dynamic warm-ups prevent injury. But studies have been increasingly clear that static stretching alone before exercise does little or nothing to help. The largest study has been done on military recruits; results showed that an almost equal number of subjects developed lower-limb injuries (shin splints, stress fractures, etc.), regardless of whether they had performed static stretches before training sessions.

Depends on your sport

[HogGeek]

Based on what I've read, stretching/warm-up should be based on your sport.

For instance, I coach a hockey team, and any stretching is considered bad, as it loosens the tendons, and you are now more prone to injury because "things" can move too far...

We (the team) do simple warm-ups.

Note to self: read linked articles before posting!

[K3ba]

Most of the negative comment posters below obviously didn't take the time to read the linked article.

Some types of stretching are good, some are bad. The article explains the differences quite well and still recommends that some stretching takes place...

Re:Muscle Cramps?

[Kijori]

Absolutely agree with everything you've posted - I was going to say the same thing. To add to that though, this isn't new at all. My exercise book from 2-3 years ago has exactly the same information - stretching will reduce performance, but it's still worth it.

20-30 sec?

[rzei]

Where did that come from? I've been taught since being a 6 year old hockey master that you should always do warm up, and then stretch max 10 seconds per muscle...

Right after exercise, you shouldn't stretch as your muscles should be full of blood, you don't want to rip them open – you should walk or do something light and go to sauna.

2-3 hrs after exercise you should do those 20-40 sec stretches.

Warm-up yes, static stretching no

[Anonymous Coward]

The article does not talk against stretching in general. It suggests that before workout, the stretches should be dynamic and only after workout static.

Weakening the muscles is a good thing

[teebes]

If you're lifting, what you want to do is to weaken your muscles enough for them to rebuild stronger. So again, starting with a weaker muscle just means that it's easier to get to the point you want. Also, as has already been mentioned, the main point is that it decreases the chance of injury. In short, keep stretching!

Not new information.

[NoPantsJim]

Google "Pavel Tsatsouline" or just go to dragondoor.com. The Russians have known about stuff like this for decades. If you're looking to lose the nerd physique like I did, pickup some kettlebells from the site. Mine are worth their weight in gold.

Please RTFA

[Timothy Brownawell]

TFA is not saying that warm-ups are bad, it actually says that they're good. What it does say, is that just stretching is not a proper warm-up. A proper warm-up has light exercise to make you, well, warm. It also says that "stretch and hold" is bad, but exaggerated movements ("dynamic stretching") are good.

Not news

[Anonymous Coward]

For what it's worth, as someone involved in the strength training community, this is not news to any serious athlete or coach. It's been known for years (decades?) that stretching before training generally decreases performance. And that, in fact, beyond achieving and maintaining the (usually rather small) amount of flexibility directly necessary for one's sport, stretching is not a productive use of training time.

By the way, geekdom and lifting weights are not incompatible! Being into writing code or whatever else doesn't mean you have to be a skinnyfat weakling!

Re:Warm-up still important

[sdpuppy]

Exactly. Unfortunately the basic principles are rarely stated; once you understand this simple principle all this advice makes sense:

1) You want to stretch ONLY muscle, rarely tendon (muscle to bone connections), and NEVER ligament (holds bones together). Think of a mechanical coupling such as ball joints in a car (yes! a car analogy!.:-) ) If they are tight, forces are transmitted as they should be. Loose couplings - not only do your teeth get rattled, but parts tend to wear out.

Back to the meat world, for example, if your collateral ligaments (sides of knee) are loose, then there is side to side play in your knee joint, your movements are less efficient, forces are applied in directions which they're not supposed to leading to injuries. (also think of football and ACL/PCL - knee ligament injuries) Now if your leg tendons are loose, your leg muscles will be like a stretched out string - less efficient in the full range of motion.

2) You want to stretch warmed up muscle, not cold, since cold will resist the movement. If you stretch cold, you will tend to stretch tendon & ligament and your body will resist more (see #1)

The trend in Yoga now is to work on positions after warm up. In the past (at least from my POV) they discouraged "pushing" into positions so injuries were averted - by warming up both by exercise (some forms combine Pilates type movements) and sometimes external heat, attaining flexibility is made more efficient and less prone to injury.
An amazing book to read on the subject of flexibility is "Science of Flexibility" by Alter. It has probably all you want to know on the subject.

Amazon link: http://www.amazon.com/Science-Flexibility-Michael-J-Alter/dp/0736048987

I've got your peer-reiviewed papers right here

[Ambitwistor]

I think this entire article is a load of attention seeking BS, and I will not believe a word of it until I see a proper peer-reviewed research paper in a medical journal that debunks stretching.

Geeze. I've noticed a certain hyper-skepticism among Slashdotters. Please note that the New York Times is not known for trumping up pseudoscience with no support in the literature.

Others have responded that the article is not "debunking stretching", just pointing out problems with certain kinds of stretching. And at least one other poster gave references, some of whom involved people interviewed for TFA. More specifically with respect to the studies mentioned in TFA:

The article cites Duane Knudson, a kinesiology professor at CSU. Peer reviewed research paper.

The article mentions a Las Vegas stretching study. Peer reviewed research paper.

The article mentions Malachy McHugh, a researcher in NYC. Peer reviewed research paper.

The article mentions a collegiate volleyball study. Peer reviewed research paper.

And so on.

Dude, that's not how muscles work

[sam_vilain]

What's this "fibres overlapping" rubbish? Muscles change shape because the cells change shape, not the fibres. Go read an anatomy book.