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Already, the benches in gym locker rooms and beside basketball courts are filling with 2012’s early casualties, those of us who, goaded by New Year’s resolutions, are exercising a bit too enthusiastically and developing sore muscles. Many of us will then drape ice packs over our aching muscles. But a new review article published this month in the journal Sports Medicine suggests that for sore muscles, ice is not always the panacea that most of us believe it to be and that, in some instances, it can be counterproductive.

For the study, researchers at the University of Ulster and University of Limerick in Ireland reviewed almost three dozen earlier studies of the effects of using ice to combat sore muscles, a practice that many who exercise often employ. Ice is, after all, the “I” in the acronym RICE (rest, ice, compression, elevation), which remains the standard first-aid protocol for dealing with a sports-related injury. Icing is also widely used to deal with muscles that twinge but aren’t formally injured. Watch almost any football, basketball or soccer game, at any level, and you’ll likely see many of the players icing body parts during halftime, preparing to return to play.

But there has been surprisingly little science to support the practice. A 2004 review of icing-related studies published to that point concluded that while cold packs did seem to reduce pain in injured tissues, icing’s overall effects on sore muscles had “not been fully elucidated” and far more study was needed.

Last year, a small-scale randomized trial found no discernible benefits from icing leg muscle tears. The cooled muscles did not heal faster or feel less painful than the untreated tissues. But, as the researchers point out, it is difficult to scientifically study icing, since you can’t blind people to whether they are receiving the therapy or a placebo. People generally can tell if their muscles are getting cold or not.

Which leaves the findings of the new review about icing by athletes as the best overview we may have for now. And the findings are not altogether comforting.

The authors write that, in a majority of the studies they looked at, icing was quite effective at numbing soreness. But it also significantly reduced muscle strength and power for up to 15 minutes after the icing had ended. It also tended to lessen fine motor coordination. Some of the reviewed studies found that people experienced impaired limb proprioception, or their sense of where their limb was in space after it had been iced.

The result was frequently, at least in the short term, poorer athletic performance. Volunteers were not able to jump as high, sprint as fast, or throw or strike a ball as well after 20 minutes of icing.

“The current evidence base suggests that the performance of athletes will probably be adversely affected should they return to activity immediately after cooling,” the authors conclude.

Why an ice pack before exercise should depress performance isn’t fully understood, though there are several theories. “The most likely reason is that ice reduces nerve conduction velocity,” said Chris M. Bleakley, a research associate at the University of Ulster who led the study. “Nerve impulses in the muscle slow down.” Cooling, he said, also probably “affects the mechanical properties of the muscle tendon unit,” meaning that the muscles and tendons, which should work together seamlessly, do not.

There’s also the possibility that icing sore muscles may increase the risk of injury, though the studies did not examine this issue directly. If your iced shoulder or legs feel sluggish during a tennis match or run, the authors suggest, you presumably will push harder, even as the iced muscle, being numb, doesn’t alert you to the beginnings of a more severe injury. The risk really applies “to situations where athletes are returning to competition immediately after icing,” like when you apply a cold pack before a run or “ice on the sidelines or at halftime to treat pain and discomfort,” Dr. Bleakley said. That means for most of us, there may be times when it’s fine to ice sore muscles – like after a hard workout or when we experience serious injury — provided we do not jump back into the field.

Most earlier studies have found little benefit from icing after exercise, but also few negative side effects. And if we must resume activity, the negative effects of icing are thankfully short-lived, usually disappearing within about 15 minutes. They also were less severe if the icing time was shortened, Dr. Bleakley says. “Application times of three to five minutes had much less of an adverse effect on performance” than keeping the ice pack in place for 20 minutes or more, he said.

The fundamental lesson of the review is clear. “Ice has many benefits,” Dr. Bleakley says. “It is cheap and remains an excellent method of numbing pain.”

Ice remains an accepted therapy for an acute injury and is popular with many athletes to help them to recover after exercise. But relying on ice to get you back into that senior-league basketball game or onto the running track when you’re already sore is inadvisable. “Athletes should consider that pain is usually a sign that something is wrong with your body,” Dr. Bleakley says. Listen, and stay out of the second half of the senior-league basketball game or skip a day’s run. You have the rest of 2012 to fulfill your resolution.