A new study is raising eyebrows among those of us who include sports medicine in our practices. Now, before I give you the details of the research, a couple of disclaimers:

• This study was published as an abstract and will be presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
• The study design included runners who were assigned either to a stretch or no-stretch pre-running routine for three months. However, even thought the study assignment was randomized, the treatment groups were unmasked; data were self-reported; runners were experienced; and adherence to practice was poor especially among those assigned to stretching. So, these data may not apply to everyone.

Nevertheless, stretching before a run is not all it’s cracked up to be for injury prevention, a researcher has suggested.
In a three-month randomized trial, self-reported injury rates that prevented running for more than three days were 16% both among the 600 participants who stretched before starting their regular runs and in the 798 who were told not to stretch.
On the other hand, stretching DID appear to protect against injuries that were bad enough to send the runner to a clinician for diagnosis, with an odds ratio of 0.60 (P=0.005) after adjusting for prior illness, chronic injury, age, body mass index, and high running mileage, reported Daniel Pereles, MD, an orthopedic surgeon and sports medicine specialist in Kensington, MD. Here are the details from MedPage Today:
Pereles shared the data before his formal presentation at the American Academy of Orthopaedic Surgeons’ annual meeting.
Most sports medicine specialists recommend stretching before any strenuous activity, particularly for older people, but scientific studies have equivocated on the injury-prevention benefit.
Edward McDevitt, MD, a sports medicine specialist in Arnold, MD., told MedPage Today that it’s hard to imagine that stretching wouldn’t be beneficial.
McDevitt, who called himself an advocate of stretching, said he couldn’t find fault with the new study’s methodology but nevertheless was reluctant to accept the results.
“I don’t have to believe every study I read,” he joked. But he said the findings suggested that more research is warranted.
No prospective, randomized trials to evaluate stretching before running-only activities have been reported before, according to Pereles.
In the current study, 2,729 individuals with regular running routines of at least 10 miles a week agreed to participate. They were randomly assigned to a prescribed stretching regimen or were instructed not to stretch.
Participants’ mean age was about 40, and their median weekly running distance was 20 miles. About two-thirds reported regular running for at least five years.
Adherence to the study protocol was poor, Pereles noted, although it was about the same as expected in such a study. Only 600 of the 1,366 participants in the stretch group stuck with the regimen adequately enough to be included in a per-protocol analysis.
Even among the 1,363 assigned not to stretch — which would not seem challenging — the compliance rate was only 57%.
Of the 1,398 participants who did adhere to their assignments for the full three months, 220 reported injuries that stopped them from running for more than three days.
About half the injuries (106) were severe enough to prevent running for at least a week, and 64 kept the runners at home for two weeks or more.
But with the exception of clinician-diagnosed injuries, none of these injury subsets were significantly more or less common with stretching.
Pereles reported one especially striking difference associated with stretching — among participants who, at baseline, said they regularly stretched before running and then were assigned to the no-stretch group, the injury rate was 22.3%.
In contrast, the injury rate was 15.6% for those in the stretch group who said they previously stretched (P<0.05), according to the per-protocol analysis.
Previous nonstretchers who were assigned to the stretch group also had higher injury rates compared with nonstretchers who didn’t switch routines (16.2% versus 11.8%, P<0.05).
In addition to changing their pre-run routines, other risk factors for injury in both groups included high BMI and a history of recent or chronic injury.
Pereles acknowledged that stretching would not be expected to affect the risk of nonmuscular injuries such as ligament tears and bone fractures. He told MedPage Today that the study was underpowered to assess effects of stretching on specific types of injuries.
For example, there were only 10 back injuries in the study.
But he pointed out that a study powered to find differences in specific injury rates could require up to 100,000 participants. Dropout rates would probably make a smaller study with longer follow-up impractical, Pereles said.
He also indicated that the study, which mainly enrolled experienced runners, would not be generalizable to novices.
McDevitt told MedPage Today that he would be concerned that publicity surrounding the study would send a message to first-time runners that they don’t need to stretch.
Pereles said he would actually recommend some type of warm-up, which may or may not include stretching, for individuals taking up running for the first time, especially if they are older and/or overweight.
McDevitt, who serves as team physician to the U.S. Naval Academy’s basketball team and is a runner himself, said the times he has gotten hurt were when he didn’t stretch.
On the other hand, Pereles said he was a long-time long-distance runner who stretches beforehand, yet has suffered a long list of injuries.