Is the clinical use of ice still relevant?

Abstract

The use of cryotherapy, or the therapeutic application of cold, has become commonplace throughout much of the sports world. It is fairly typical to see a pitcher in Major League Baseball in the USA walking around with his entire arm wrapped in ice after he pitches, or to read testimonials of athletes in a variety sports about their experience in a cryochamber. Nevertheless, this propensity of use does not appear to be substantiated by research. Bleakley et al. (2004) concluded in their systematic review that insufficient evidence exists to support the use of cryotherapy clinically. Additionally, Hubbard & Denegar (2004) state that ‘the exact effect of cryotherapy on more frequently treated acute injuries has not been fully elucidated’. In this issue of Experimental Physiology, Lindsay et al. (2016) set out to elucidate the effects of repetitive cryotherapy in a mixed martial arts population. Using a population of 14 mixed martial artists, the scientists conducted an in vitro and an in vivo study to determine whether or not repetitive cryotherapy treatments affected the immune response to exercise. Their results were enlightening. In the in vitro and in vivo samples, T-cell and monocyte activation was decreased, whereas physical performance was not. The physical performance measurements included standing broad jump, press-ups and pull-ups. These data are meaningful because they get beyond the shortcomings of the studies discussed by Bleakley et al. (2004), more fully elucidating what is happening when someone treats with ice. A few questions arise from this study. First, are these results generalizable to an injured population? Many scientists have used delayed-onset muscle soreness as a model to study injury, yet it has not been proved that the inflammatory process associated with an injury truly acts the same way. The authors should be commended for using a population whose activities could more easily result in injury, but the question of generalizability remains. Second, do we want to decrease the immune response? The proponents against the use of cryotherapy use this as their main argument. If the inflammatory process is slowed, is healing slowed too? This is definitely something that must be studied further. Third, how closely do the treatment parameters reflect cryotherapy usage practices? In my experience, the use of cold water submersion tends to be something done regularly at the beginning of a sport season but gradually decreases over the first week or two. Admittedly, I have not spent any time in a mixed martial arts gymnasium, so I do not know whether the methods used in this article are customary in that setting. The authors’ results seem to indicate, however, that if regular cold water immersion is not used, should it be? When looking at the clinical use of cryotherapy as a whole, I believe confusion exists regarding when to use the modality. Furthermore, there is a lack of understanding that cryotherapy serves different purposes in certain situations. The article by Lindsay et al. (2016) is a step in the right direction to helping us understand what role cryotherapy plays in the treatment and rehabilitation of injury. Future studies may focus on the treatment of injuries experienced by this population as well as what temperature the water must be at to obtain the same benefits. Both studies would be enlightening, while helping us to understand this frequently used therapeutic modality.