Article from AUSTRALIAN DOCTOR WEEKLY journal 6 Jan 1989, Sports science section, reported by medical writer, Rick McGuire
Blisters seems to be an ongoing subject for debate. Many runners still continue to use either cotton socks or mixtures, both conducive to the formation of blisters. Unfortunately, many big name manufacturers still continue to make blends of synthetic and cotton, which, while quite suitable for casual wear, are a disaster for runners.
Since nearly all athletic footwear studies have focused on shoes, the California College of Podiatric Medicine decided to test how socks affect foot problems. The investigators were astounded by the results.
Apparently, natural is not always best. Acrylic socks were found to be clearly superior to cotton socks for the prevention of blister formation in runners.
Dr.Douglas Richie stated "we were astounded. Our data are in direct conflict with currently held recommendations by coaches, athletic trainers, sports physicians and athletes who should all reconsider the notion that cotton socks are superior in vigorous athletic activity."
The data was presented during a meeting of the American Podiatric Medical Association (APMA) and he underscored that the common belief of the superiority of cotton socks was not based on any objective evidence.
"In preparing to do our study, we could not find any scientific evidence that has proven the validity of the recommendation for natural fibres" Dr.Richie said, "yet the advantages of natural fibres continue to be propagated year after year."
At the APMA meeting, he presented the results of the double-blind crossover study which involved 60 long distance runners in 800 runs averaging some fifty minutes each. The acrylic socks were superior in preventing friction blisters and dissipating moisture. In general, cotton socks produced twice as many friction blisters, and the blisters so formed were three times the size of those seen on runners wearing acrylic socks.
Why is cotton harder on the feet? "First, laboratory studies suggest that acrylic fibres are wicking moisture off the surface of the foot and that reduces the friction co-efficient on the surface of the skin," Dr.Herring, study co-ordinator said. "Secondly, cotton has an inherent tendency to compact as it gets wet and to become abrasive with repeated use causing a greater friction co-efficient against the skin."
Although the vacillating consumer might try to get the best of both worlds, Dr.Richie suspected that the worst sports sock might actually be a blend of synthetic and cotton, explaining that natural fibres deteriorate faster than acrylic fibres. Thus, as the cotton deteriorates over time from wear and washing, those fibres would tighten causing bunching and an irregular wear pattern with perhaps an even higher friction co-efficient than either pure cotton or pure synthetic socks.
Dr.Ritchie isn't expecting to change sports medicine advice overnight. He noted that the favoured status of cotton is so ingrained that many authorities have been "outraged" by his data. The bottom line, he said, is that no one has ever questioned if there is any scientific validity to the past recommendations favouring natural fibres for athletic socks. But now there is evidence and we're so confident that now we can tell anyone that there is no question that when it comes to blisters, synthetic fibres are the correct choice.
(end of article)
Footnote by Dr.Graham Sayer, medical scientist, Gold Coast
I fully endorse this study and its findings. The first 10 years that I ran distance, I used either pure cotton or a combination of cotton/synthetic fibres with frequent blistering of the feet. The last 25 years, I have used only synthetic fibre socks (acrylic, stretch nylon, spandex, dacron, lycra etc.) and there has never been a blister since. Additionally, it is important to mark socks "left" and "right" at time of purchase and not to switch them around to either foot.