The first study to compare the effect of cold water immersion versus extreme cold air has found very little difference between the two treatments on athletes' muscle recovery.
Cold water immersion has become popular among sportsmen and women to cool strained muscles in order to recover faster, compete again sooner and to train harder.
Treatment in cold water immersion was compared to treatment in extremely cold air (below -100°C), a relatively new method of speeding up recovery and regarded by some elite athletes and coaches as a step forward, a superior treatment.
Cold air exposure typically lasts for three minutes in a specialized cold air chamber, an ice bath typically lasts for 10 minutes.
Until now, there has been limited research directly comparing the two treatments.
This new study, led by Dr Erich Hohenauer at the University of Applied Sciences and Arts of Southern Switzerland, found both cold water immersion and the partial-body cryotherapy treatments resulted in similar recovery during a 72-hour follow-up period.
The research is published the Scandinavian Journal of Medicine and Science in Sports.
Leading expert on cryotherapy, Dr Joe Costello, of the University of Portsmouth, is one of the study's authors.
He said: "The use of cryotherapy is very popular in elite sport. For example, various premier league teams currently use the treatment. However, we know very little about the effectiveness of the treatment; in particular we do not know if the cryotherapy is more, or less, effective than ice baths.
"Our results clearly demonstrate that, in terms of athletic recovery, there are no differences between cold water immersion and the partial-body cryotherapy."
Dr Hohenauer said questions over the value of such treatments came first from elite sport but increasingly sportsmen and women at all levels were interested in ways of recovering faster and performing better.
He said: "Cold water immersion is well established in sport science as a way of speeding up recovery. Cryotherapy is relatively new and science is only now catching up in order to examine whether it works, and how.
"It's conceivable that cryotherapy might one day replace cold water immersion however, more research is needed to establish the optimal cooling dose."
In the study of 19 men there was a significant physiological difference – including oxygen levels in thigh muscles and skin temperature – between the two treatments in the immediate term. But within hours there was no difference in how the men felt and no measurable physiological benefit of one treatment over the other.
In previous research for the Cochrane review, Dr Costello found only some evidence to support the use of whole-body cryotherapy as a recovery method.
Athletes, including footballers and rugby players, and those competing in tournaments over one or two weeks, rely heavily on sports scientists helping them recover quickly before their next bout.
Dr Costello said: "These findings might also help inform coaches when making decisions about which recovery method to use for their athletes.
No evidence that whole-body cryotherapy enhances athletes' recovery
by Niki Widdowson, Queensland University of Technology
Rugby World Cup teams such as England, Wales and Georgia using whole-body cryotherapy to speed muscle recovery may not be getting the edge over those teams using traditional methods, a world-class review of top sports science studies suggests.
The review was conducted by the Cochrane Collaboration, the gold standard for medical reviews and evidence-based practice, on studies which had investigated whether whole-body cryotherapy (WBC) was superior in reducing muscle soreness and improved recovery and safe.
Professor Philip Baker, Associate Professor Ian Stewart and Dr Geoffrey Minett from QUT's Institute of Health and Biomedical Innovation joined some of the world's leading practitioners and researchers in athletic recovery from the UK, France, and Northern Ireland on the Cochrane Collaboration review panel.
Dr Minett said there was some scepticism in the elite sporting community about the benefits of WBC over other treatments and little quality research had been done on it.
"WBC involves single or repeated exposures to extremely cold dry air (below -100°C) in a specialized chamber or cabin for two to four minutes per exposure," Dr Minett said.
"It is suggested that it improves recovery and reduces muscle soreness after exercise and is gaining popularity in elite sport as a way to quickly recovery after a test match or hard training."
Dr Minett said rugby players experienced a great level of muscle damage.
"Not only from collisions while tackling or in the ruck, but also from the high number of repeated sprint efforts completed during a match," he said.
"The idea is that WBC reduces the inflammatory process to allow the muscles to recover more quickly and enhance their training quality and return to fitness."
Dr Minett said the review team analyzed the four published studies that compared WBC with either passive rest or no treatment. They found no studies that compared it with other cooling interventions such as cold water immersion.
"In all, the four studies reported results for 64 physically active predominantly young adults with a mean age of 23, including only four women.
"None of the studies reported active surveillance of predefined adverse events, though there is one report of frost bite in the literature.
"In fact, the evidence for all outcomes in the fours studies was classified as 'very low' quality."
Dr Minett said the review panel concluded there was insufficient evidence to determine whether WBC reduces self-reported muscle soreness or improves subjective recovery after exercise when compared with passive rest or no WBC.
"The lack of evidence on adverse effects on the athletes is concerning because exposure to extreme temperature presents a potential hazard," he said.
"Until there is definitive evidence that WBC lives up to its claims, it might just be an expensive, uncomfortable fad."