(Reprinted from the Georga Tech Sports Medicine & Performance Newsletter, Vol. 7 No. 9 May 1999)

Athletic shoes get most of the publicity, but serious athletes recognize that the socks inside those shoes can affect performance and prevent injuries.

Douglas Richie, Jr., D.P.M., a Los Alamitos, California, sports medicine podiatrist, presented findings on sock research in an address delivered to the American Academy of Podiatric Sports Medicine.  Following are some of his conclusions regarding friction blisters, fibers used to manufacture athletic socks, shoe/sock fitting considerations, and sport-specific sock design.

Friction Blisters

The wrong type of socks can lead to blood clots, infections, bunions, bursitis, contusions, and other conditions.  But friction blisters remain the most common injuries affecting exercisers (as high as 70 percent), a fact confirmed by several studies involving military trainees.  The factors that have to be present for blisters to develop are side-to-side movement, pressure, and moisture.  The effects of all three can be lessened by wearing proper socks, wearing two pairs, or applying petroleum jelly to sensitive areas.

Fibers

Richie and his colleagues found that runners who wore acrylic fiber socks had fewer and smaller blisters than those who wore cotton fiber socks.  The results of the research were significant only when the acrylic socks were constructed with dense terry padding rather than in generic cushion-sole socks.

A study of Marine recruits showed that the use of a Coolmax(TM) liner with a heavily padded outer sock design using a wool/polypropylene blend significantly reduced blisters when compared to a single layer sock.  Although research is ongoing, there are indications that socks made with a combination of teflon (Blister Guard(TM)) and other synthetic fibers are also effective in reducing blisters.

Fibers that simultaneously repel sweat and expose it to the air for quick evaporation are ideal.  Fibers that wick moisture, from best to worst are Coolmax(TM), acrylic, polypropylene, wool and cotton.  In addition to its bottom ranking, cotton athletic socks lose their shape, bunch, and become more abrasive over a period of time than acrylic fiber socks.  Polypropylene socks worn on top of orthotics can be slippery.

Stephen Pribut, D.P.M., who is on the faculty at George Washington University in the District of Columbia, adds these comments to the discussion of fibers.   "There is simply no useful role for cotton socks in sports or even in casual wear.  Materials that wick moisture away from the skin rather than holding it are important in preventing skin maceration (soft skin caused by constant exposure to moisture), blisters, and athlete's foot."

Pribut points out that clean socks are also vital.  "You should not work out two days in a row in the same socks.  It is even helpful to change socks if you exercise more than once during the same day."

There are some cold weather activities in which protection against heat loss is especially important. A synthetic fiber with a hollow core called Thermax(TM) insulates against heat loss.  Natural wool would provide even more insulation, but it's too abrasive.  Unless wool fibers are blended into synthetic materials, avoid wool athletic socks.