מאמר באנגלית על שימוש בגרב קולמקס ושיטת גרבים-כפולות.

Blisters and Other Skin Injuries

Friction blisters are among the most common foot injuries affecting the athlete. Blisters on the feet are even more prevalent and debilitating in military recruits. A study performed on 357 marine recruits at Parris Island, South Carolina, revealed a 69% prevalence of blisters during a four-month period of training. Blisters serious enough to warrant medical evaluation at sick call occurred in 24.4% of all trainees. It has been estimated that over 5,000 Basic Trainees at Lackland Air Force Base were treated for friction blisters during one calendar year in 1990.

Factors necessary for friction blisters are shear force, pressure and moderate levels of moisture. All of these forces can be mitigated by a proper sock system.

Herring and Richie investigated the role of fiber and sock construction techniques in the prevention of blisters on the feet of running athletes. Their findings demonstrated that acrylic fiber socks will have less blisters and smaller blisters than cotton fiber socks. In addition, athletes were able to determine a drier foot with acrylic socks compared to cotton.

These findings were significant only when socks were constructed with dense terry padding rather than in generic "cushion-sole" socks.

Plagued with ever-increasing frequency of blisters, the United States Military conducted three randomized prospective studies on various sock systems. The standard military issue sock is a 50% cotton and 50% wool cushion-sole sock. The three studies attempted to compare newer fiber construction techniques and double-layer technology to reduce blister frequencies.

In a study of 357 marine recruits on Parris Island, South Carolina in 1992, the use of a CoolMax® liner with a heavily padded terry design outer sock using a wool/polypropylene blend significantly reduced blisters compared to a single layer sock (40% vs. 69%). Adding a CoolMax® liner to the standard sock significantly reduced sick call visits (24.4% standard vs. 9.4% standard with liner).

Another study of 1,079 soldiers in 1993 tested five sock systems on blister frequency and acceptability by soldiers. Synthetic fiber socks significantly outperformed the standard wool sock. Adding a CoolMax® liner to the wool sock significantly reduced blisters. When comparing single, extra-thick acrylic padded socks to double layer sock-systems, the double-layer system was superior owing to the shielding of the open terry loops from the skin surface and the movement interface created by the double-layer system. Three other military studies have demonstrated a blister prevention superiority of double sock systems vs. single layer socks.