A new study says it may not actually help a muscle strain recover faster, but that's not the whole story behind icing sports injuries. Our experts weigh in

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One of the biggest debates in sports injuries is whether heat or ice is more effective in treating a muscle strain-but what if the cold is not only less effective than warmth, but isn't effective at all? Turns out, icing injured muscles may not actually help speed recovery time or muscle healing, reports a new paper presented last week at the Experimental Biology Meeting. (The easiest fix? Avoid them to start with! 5 Times You're Prone to Sports Injuries.)

Australian researchers treated rats with muscle contusions-which are basically muscle bruises, the second most common sports injury next to strains-with ice compresses within five minutes of the injury for 20 minutes total. Compared to injured rats who received no help, the ice group had lower inflammatory cells and higher blood vessel regeneration for the first three days-good news, since both of these cause swelling. However, after seven days, they actually had more inflammatory cells as well as fewer new blood vessels forming and less muscle fiber regeneration. These unhelpful responses continued for the rest of the month after injury.

These results are intriguing, even if the study is still preliminary and hasn't been confirmed on humans. But while this does add to the debate over whether ice really does slow down the healing process or not, science has proven ice good for something: decreasing the pain of muscle injuries, says Timothy Mauro, certified physical therapist and partner at New-York-based Professional Physical Therapy. "Ice limits the nociceptive response-that of your nerve cells-which decreases pain," he explains. (It also helps more innocent post-workout aches, along with these 6 Ways to Relieve Sore Muscles After Overtraining.)

It's not just about comfort. Less pain allows you to be more active, engaging the muscle and furthering rehabilitation, says Rose Smith, certified physical therapist and associate professor of rehabilitation sciences at the University of Cincinnati. "Icing wouldn't allow someone to perform at the previous level, but it does help to allow rehab to continue," she adds. Plus, pain inhibits strength-a major goal of rehabbing an injured muscle, Mauro adds.

Despite this study's findings, both Smith and Mauro still recommend applying ice immediately after an injury to help with pain and immediate inflammation. Once the swelling sets in, though, you should stop icing, start light exercise (like short walks), and elevate the muscle when not standing, Smith says. And consider the heat method: According to the Mayo Clinic, the best way to treat sore muscles is with cold therapy first and heat therapy later, since warmth promotes better blood flow and circulation to the area, eliminating the buildup causing the swelling. (Plus, 5 All-Natural Remedies for Sports Injuries.)