Get-Fit Guy looks at the science behind icing sore muscles, plus has tips on how to make the most of Rest. Ice. Compression. Elevation.
The first study commonly cited is “The Use of Cryotherapy in Sports Injuries.” But if you look closely at this study, the researchers simply conclude that “cold can inhibit inflammation as well as enhance inflammation.” It certainly is true that when ligament injuries were induced in pigs (this is similar to the type of injury you might get when weight training), swelling was greater in ice treated limbs. However, in this study (as well as in another study entitled “Cryotherapy Influence on Posttraumatic Limb Edema”) animal subjects were subjected to long periods of icing up to 1 hour in length. And a full hour of icing is a period of time that you’d be hard pressed to find any sports medicine professional recommending.
In addition, in the first study I just mentioned, it was demonstrated that permeability of the lymph vessels does actually increase with icing, but that within 25 minutes after icing, the permeability of the lymph vessels returns to pretreatment levels. Finally, it was simply ice used in both these studies – with no compression (pressure) or elevation (two other injury protocols that are highly recommended by sports medicine professionals). The majority of studies that combine ice with compression and elevation do not show the same permeability increase or resultant swelling with cold treatment. This is because compression from pressure placed upon an injured area reduces swelling and prevents fluid from leaking out of the vessels.
Of these 10 studies, 6 were trials in humans, but 4 of them were thrown out because of poor research!
Another study commonly cited in the argument against icing is the 2008 study “Is Ice Right? Does Cryotherapy Improve Outcome for Acute Soft Tissue Injury?” This was basically a literature review of 10 studies. Of these 10 studies, 6 were trials in humans, but 4 of them were thrown out because of poor research. The additional 2 human studies were split, with one of them supporting cooling, while the other lacked statistical significance to show icing’s efficacy. Four animal studies in this review showed reductions in swelling from ice application. The final two pieces of literature cited were systematic reviews, one of which was inconclusive and the other suggesting that ice may hasten return to participation. None of these results justify tossing your ice bags into the trash bag, but again simply suggest that icing by itself may not work in some cases.
Finally, a 2010 study was performed at the Neuroinflammation Research Centre at the Cleveland Clinic in Ohio, and was instantly heralded across the press as conclusively revealing that “putting ice on injuries can slow healing.” But laughably, a closer look at this study reveals that no ice or cold treatments were used at all! Researchers simply studied two groups of mice: one group that was genetically altered so they could not form an inflammatory response to injury, and a second group that was normal.
The researchers then injected the mice with barium chloride to induce muscle injury, and found that the mice who were genetically altered to not form an inflammatory response to injury did not repair their damaged muscle. So this research simply demonstrated that the complete absence of inflammation will shut down the muscle healing response – but did not investigate the effect of ice at all! This is clearly an example of How the Media Sensationalizes Science.
So what we have learned so far is that icing sometimes works and sometimes doesn’t – and the times that icing doesn’t work is when you ice for very long periods of time or when you ice without also using pressure or elevating the area you’re icing.