The term cryotherapy refers to the application of something cold to the muscles and the idea behind its use is as an aid for recovery in the athletic world. Yet, study after study shows only a benefit to soreness and an improvement in perceived levels of recovery. Those are good things, but the problem is cryotherapy doesn’t seem to actually benefit performance.

Most of the cryotherapy research to date has involved using the therapy between workouts. Cooling the muscles after one workout helps with soreness for the next workout, but seems to make no difference in any of the studied performance variables. However, in a study this month in the Journal of Strength and Conditioning, researchers took a different perspective. Although cryotherapy doesn’t seem to boost performance between workouts, the researchers hypothesized that it might work within a given workout.

Cryotherapy can involve the use of bags of ice, ice packs, cooling garments, or cold water. When using water, you’ll often hear the term hydrotherapy as well. Hydrotherapy can be hot or cold, or in the case of contrasting hydrotherapy, both hot and cold. In this study the researchers used ice bags, which is perhaps the simplest and most accessible method for most of us.

Most people know cold is a vasoconstrictor, meaning it causes the blood vessels to constrict, thereby generally reducing blood flow. Most of the time, this would be a bad thing, since it would decrease the amount of blood available for the muscles to use and negatively impact performance. But this isn’t why researchers, athletes, and coaches are interested in cryotherapy.

When you exercise your muscles and other tissues swell due to the exerted effort, extra blood flow, and heat generated by the activity. The tissues exert force on the blood vessels. To a small degree, this effect can be beneficial, since it actually increases the rate at which nutrients enter the cells. However, at a certain point the pressure on the blood vessels becomes too much and their blood flow is limited. Once the blood vessels are blocked because of tissue swelling, cryotherapy becomes advantageous. Not only is it a vasoconstrictor, but it also reduces the swelling of all the tissues, and actually improves blood flow.

In this study, the researchers studied college-level pitchers. The highest relative forces a pitcher experiences are at the shoulder and elbow joints, and pitching performance is easy to measure by the speed of the pitches. These qualities made pitchers an ideal group for this particular test. Because pitchers were used for the study, the research applies especially to athletes who get an opportunity to rest and apply ice during their sport.

The researchers made up a simulated five inning baseball game – incidentally, the number of innings needed for a pitcher to be credited with a win – and had the pitchers perform up to sixty pitches total during that time, not including warm ups. The researchers measured pitching speed and either used ice on the pitchers' shoulders or elbows between rounds, or did not use ice at all.

Not only did the cryotherapy help with perceptions of exertion and recovery, as it did with previous studies, but it also improved performance. When the pitchers used ice, they pitched faster, especially in the fourth and fifth innings, which indicates the ice reduced fatigue in later innings.

So while cryotherapy may not work as a longer term recovery aid, it does seem to be effective during an actual event, at least in preventing fatigue.