Stretch the truth

Published on Friday 21 March 2008 12:33

New research has put the conventional warm-up routine on the rack

EVERYONE from your granny to your fitness trainer will tell you that stretching before exercise is a must. The runner who sets off without extending his Achilles tendons is simply trotting towards trouble.

Yet dissenting voices are making themselves heard. Stretch after your workout, some say. No, don't even bother stretching. Reaching for the sky, these voices suggest, has been oversold as a way to prevent injury or improve performance.

The truth is that after dozens of studies and years of debate, no one really knows whether stretching helps, harms or does anything in particular for performance or injury rates. Yet most athletes remain convinced that stretching is beneficial, and recently more have felt the pressure to limber up, in part due to the popularity of yoga.

"I always feel athletes should do yoga," says Claire Brown, a 35-year-old triathlete. "It's supposed to be really good for running, and when I do it regularly it does loosen up my hips and make me feel better for running."

At almost every level of sport, you see athletes, from footballers to sprinters, stretching and warming up before an event. Most swear these exercises are crucial.

If your goal is to prevent injury, stretching does not seem to be enough. Warming up, though, can help. If you start by moving through a range of motions you'll use during the activity, you are less likely to be injured.

Some athletes – gymnasts, hurdlers and swimmers among them – may need to stretch to gain the flexibility they need for their sport. But it is still under debate whether distance runners benefit from being flexible. In fact, a recent study in the US showed that the most efficient runners, those who exerted the least effort to maintain a pace, were the stiffest.

That study involved 100 people who were examined with 11 flexibility tests. They then walked and ran while the researchers measured their efficiency. Those who were the most flexible expended 10–12% more energy to move at the same speed when compared with the least flexible.

But that study did not involve stretching – it could be that the most flexible people would have been flexible with or without stretching. And even when studies do ask whether performance changes after a stretching programme, they usually involve artificial laboratory situations, says Dr Christopher Morse, an exercise physiologist at Manchester Metropolitan University. "The problem is that what is studied in the lab has very few intrinsic links to what is happening when people actually exercise."

Stretching can make you more flexible, but does it change a naturally efficient runner into an inefficient one? No one knows, Morse adds, but there also is no evidence that it does.

And while holding a stretch temporarily reduces muscle power when measured in the lab, many people also warm up in real life, counteracting stretching's negative effect and enabling muscles to work with full force. That means, he says, that those studies showing stretching makes muscles temporarily weaker "might have no real-world consequences".

While academics argue over the merits of stretching, it seems most amateur sportsmen and women are in little doubt. "I would never consider starting off on a run without stretching and warming up. It even helps psychologically," says 30-year-old Alison Allan, who runs up to five miles four times a week.

"Fortunately, I have never had any serious injury, but on the few times I have run without warming up, I have really felt it in my muscles afterwards. I just wouldn't take the risk of not stretching."