Most runners, whether they’re training for a marathon or simply out to get some exercise, will stretch before they take off. It’s a ritual that verges on the sacred, strongly connected to the intuitive sense that priming the muscles is a good way to avoid injuring them during the run to come.

But researchers at George Washington University and the USA Track and Field Association (USATF) report that stretching before a run does not appear to reduce injury at all. In fact, among the more than 2,700 runners in the study, ranging from recreational runners to competitive marathoners, all of whom ran at least 10 miles a week, the scientists found similar injury rates — of about 16% — over a three-month period among those who stretched before running and those who did not.

The idea behind stretching is to lengthen the muscle fibers to increase their function and hopefully enhance performance, helping runners maintain a faster pace or run for a longer period of time. A study of British recruits in the military found that a regular stretching routine before training reduced injury rates from 6% to 1%. But other recent studies among gymnasts, football players and wrestlers have questioned the practice, suggesting that stretching does not impact performance at all.

That’s why Dr. Daniel Pereles, a runner himself, decided to look specifically at the role that stretching might play in running injuries. Most studies on the subject, including the British trial in the military, involved stretching routines that included much more than stretching running muscles; they also incorporated calisthenics and other exercises. Pereles wanted to know specifically whether stretching leg muscles — the quadriceps, hamstrings and calf muscles — would have an impact on injuries.

Through the USATF, Pereles was able to recruit enough runners of various levels to get an answer to his question. About half of the 2,729 volunteers were told to stretch their quads, hams and calf muscles for three to five minutes before running for however long they usually exercised. The remaining half were told to run without stretching.

While he found that stretching did not have any effect on injury rates among the two groups, he did find several factors that did seem to influence whether the runners hurt themselves. Heavier runners, as well as those who had recently suffered an injury, were more likely to harm themselves. Interestingly, Pereles also found that those who switched from a stretch to non-stretch or non-stretch to stretch routine for the study were more likely to get injured. Stretchers who were told not to stretch during the three-month study increased their risk of injury by 40%, while those who switched from not stretching to stretching increased their risk by 22%.

Pereles is still at a loss to explain that trend, although he suspects the change in routine accounts for most of the result. “It’s completely confounding, but by switching routines, it somehow messed them up,” he says.

That’s why his advice, as both researcher and runner, is to stick with what works for you. “If it feels good for you to stretch before you run, then continue if you have the time,” he says. “But if it doesn’t feel good, and you like to run and then stretch, or not stretch at all, then that’s fine too. I can’t tell anyone there is conclusive evidence that stretching makes a difference in injuries or performance.”

He notes that professional athletes, who often spend as much time stretching and warming up as they do training, are combining stretching with other activities for a more dynamic warm-up. Most recreational runners, however, don’t have the luxury of spending that much time exercising. Pereles himself admits to changing his running routine as well, and stretching only a little before a run. Part of the reason, he says, is because he doesn’t have the time, and but part of the reason has to do with the science, which so far suggests that it doesn’t seem to make a difference in injury rates.




Are Your Medications Harming Your Running?


By Laurel Leicht

From the September 2010 issue of Runner’s World 

Running keeps you healthy. even active people sometimes need medications—and when you do, telling your doctor you’re an athlete is key. “Exercise can affect how certain drugs work,” says Lori Mosca, M.D., director of preventive cardiology at New York-Presbyterian Hospital. “And certain drugs affect how you feel while exercising.” So before you pop a pill, do your homework.


Treat sneezing, itchy eyes, runny nose

WHY WORRY: Benadryl and Tavist can cause sluggishness and slow reaction times, says Marjorie L. Slankard, M.D., of Columbia University College of Physicians and Surgeons.

WHAT INSTEAD: Dr. Slankard recommends Claritin and Zyrtec (over-the-counter) and Clarinex and Allegra (prescription)—all have fewer side effects.


Treat high blood pressure, heart palpitations, migraines

WHY WORRY: Beta-blockers may cause fatigue. And because they lower heart rate, they can make it tough for your heart to perform at its peak, making even easy runs feel challenging. That’s why Heather Gillespie, M.D., team physician for UCLA Athletics, says she’d never put a runner on beta-blockers.

WHAT INSTEAD: Opt for calcium-channel blockers, ACE inhibitors, and angiotension receptor blockers (ARBs).


Treat bacterial infections

WHY WORRY: Research shows that taking antibiotics in this family (Cipro, Levaquin, Floxin, Noroxin) triples the risk of Achilles injuries. And your Achilles may be vulnerable for months after your prescription runs out.

WHAT INSTEAD: “If I have an active patient, I’ll give them a different antibiotic, like penicillin,” Dr. Gillespie says. NS


Treat pain relief

WHY WORRY: Nonsteroidal anti-inflammatory drugs (Advil, Aleve, Naproxen) can impair kidney function when taken in excess before or during a run, especially if the user becomes dehydrated, says David Nieman, M.D., of the North Carolina Research Center and Appalachian State University. Dr. Nieman studied participants of the 100-mile Western States Endurance Run who used ibuprofen to manage discomfort. After the race, he measured participants’ muscle soreness and found that the pill-poppers felt just as achy as those who hadn’t medicated.

WHAT INSTEAD: If you need to pop something before you hit the road, you probably need a rest day. Running through pain could lead to injury. Postrun, Dr. Gillespie recommends acetaminophen (Tylenol), which has fewer side effects.


Treat depression

WHY WORRY: Tricyclics (Endep, Sinequan) cause increased heart rate, which can make you tire faster on a run. They can also cause lightheadedness and delay electrical conduction in the heart, which can lead to an irregular heartbeat.

WHAT INSTEAD: In some cases, regular exercise can be enough of a mood-booster to reduce reliance on these drugs. If not, selective serotonin reuptake inhibitors (Prozac, Paxil, Zoloft) have fewer side effects. “They still increase heart rate a bit,” Dr. Gillespie says. “But they’re better for active people.”





For decades, endorphins have hogged the credit for producing “runner’s high,” that fleeting sense of euphoria and calm that many people report experiencing after prolonged exercise. Who among us, after an especially satisfying workout, hasn’t thought, “ah, my endorphins are kicking in.” Endorphins are the world’s sole celebrity peptide.

Endorphins first gained notoriety in exercise back in the 1980s when researchers discovered increased blood levels of the substance after prolonged workouts. (Endorphins, for those who know the word but not the molecules’ actual function, are the body’s home-brewed opiates, with receptors and actions much like those of pain-relieving morphine.) Endorphins, however, are composed of relatively large molecules, “which are unable to pass the blood-brain barrier,” said Matthew Hill, a postdoctoral fellow at Rockefeller University in New York. Finding endorphins in the bloodstream after exercise could not, in other words, constitute proof that the substance was having an effect on the mind. So researchers started to look for other candidates to help explain runner’s high. Now an emerging field of neuroscience indicates that an altogether-different neurochemical system within the body and brain, the endocannabinoid system, may be more responsible for that feeling.

In a groundbreaking 2003 experiment, scientists at the Georgia Institute of Technology found that 50 minutes of hard running on a treadmill or riding a stationary bicycle significantly increased blood levels of endocannabinoid molecules in a group of college students. The endocannabinoid system was first mapped some years before that, when scientists set out to determine just how cannabis, a k a marijuana, acts upon the body. They found that a widespread group of receptors, clustered in the brain but also found elsewhere in the body, allow the active ingredient in marijuana to bind to the nervous system and set off reactions that reduce pain and anxiety and produce a floaty, free-form sense of well-being. Even more intriguing, the researchers found that with the right stimuli, the body creates its own cannabinoids (the endocannabinoids). These cannabinoids are composed of molecules known as lipids, which are small enough to cross the blood-brain barrier, so cannabinoids found in the blood after exercise could be affecting the brain.

Since that 2003 study, a flurry of research has been teasing out the role that endocannabinoids play in the body’s reaction to exercise. In some of Dr. Hill’s work, for instance, rats treated with a drug that blocked their endocannabinoid receptors did not experience the increase in new brain cells that usually accompanies running, suggesting that a well-functioning endocannabinoid system may be required for cognitive improvements from exercise. Other researchers have found that endocannabinoids may be what nudge us to tolerate or enjoy exercise in the first place. In an experiment published last year, groups of mice were assigned either to run on wheels or sip a sweetened drink. Running and slurping sugar previously were identified as pleasurable behaviors in animals. Now the researchers saw that both activities lit up and sensitized portions of the animals’ endocannabinoid systems, intimating that the endocannabinoid connection may lend both exercise and dessert their appeal.

But perhaps the most telling experiment was published last year by researchers in France who had bred mice with no functioning endocannabinoid receptors. Mice usually love to run, but the genetically modified animals, given free access to running wheels, ran about half as much as usual. Although the full intricacies of the endocannabinoid system’s role in motivating and rewarding exercise is not yet understood, it seems obvious, the researchers say, that the cannabinoid-deprived mice were not getting some necessary internal message. Typically, the endocannabinoid system “is well known to impact onto central reward networks,” the authors write. Without it, exercise seemed to provide less buzz, and the animals didn’t indulge as much.

Whether this accumulating new science establishes, or ever can establish, definitively, that endocannabinoids are behind runner’s high, is uncertain. As Francis Chaouloff, a researcher at the University of Bordeaux in France and lead author of the genetically modified mouse study, pointed out in an e-mail, rodents, although fine models for studying endocannabinoid action, “do not fill questionnaires to express their feelings related to running,” and runners’ high is a subjective human experience. Still, endocannabinoids are a more persuasive candidate, especially given the overlap between the high associated with marijuana use and descriptions of the euphoria associated with strenuous exercise. One recent review article described them: “pure happiness, elation, a feeling of unity with one’s self and/or nature, endless peacefulness,” and “inner harmony.” Ahhhh.




Patrón de pronación de un corredor neutro

Pronation pattern of a neutral runner


Underpronation (also known as supination)

Sobrepronación (también conocida simplemente como pronación)


Pronation is the way the foot rolls inward when you walk and run. It is part of the natural movement that helps the lower leg deal with shock. Some people pronate more (overpronation) or less (underpronation) than others. Though this is not bad in itself, it does affect the way you run and it may increase the likelihood of injury. This makes your pronation pattern an important factor in choosing the right running shoes.



How to Enhance Training and Recovery without Hindering Performance

How to enhance training and recovery without hindering performance

By Steve Magness

As featured in the Web Only issue of Running Times Magazine

As competitive runners, we are trained to do everything we can to minimize damage and enhance recovery. Whether it is taking in a carbohydrate drink during the long run or making sure to suffer through an ice bath following that tough interval workout, trying to maximize recovery and minimize soreness and damage is ingrained in us as runners. But what if damage is a good thing?



In the world of marathoners, “hitting the wall” happens when a runner depletes his or her energy and has no choice but to slow down. Now, a new study promises a mathematical solution to keep runners far from that wall.



A Marathoner's Body

If you stand near the finish at Sunday’s Marine Corps Marathon, you will see many examples of the body’s remarkable ability to adapt to endurance training. Hang around awhile and you’ll also see what happens when certain bodies didn’t train as hard as they should have. A body won’t be ready to run 26.2 miles without some inner adaptations. Click on the above link to see a few of them.