THE SECRETS OF GOOD HIKING SOCKS
Hiking socks may seem like a generic item, but they are not - their materials, thickness, and construction greatly affect their performance.
Most hiking socks are made from synthetics (mainly polyester), merino wool or blends of wool and various synthetics such as nylon for improved durability or spandex for improved fit.
Wool is a standard material for socks. Being a natural fiber, it is hydrophilic but has some other positive characteristics of benefit for hiking socks (or other sports socks). Generally, wool socks cushion your feet, keep them warm in winter and cool in summer, wick away sweat, and retain warmth when wet. Feet can give off a great deal of moisture. All of this liquid cannot escape through your footwear. Wool socks will absorb some moisture until it can pass through your footwear or go out at the ankles. Wool is a good insulator and also keeps its shape when damp which reduces the danger of your wool socks causing blisters. One of the typical characteristics of wool is that it feels warm when wet - wool can absorb up to 30 percent of its own weight in moisture and still feel dry and warm. It is also odor resistant. Wool is relatively durable but isn’t very abrasion-resistant, however, so nylon is often added as reinforcement at the heel and toe.
Specialized wool yarns known as Merino wool have been developed that have many of the characteristics of synthetic fibers. Compared with traditional wool, Merino wool has longer, softer, and finer fibers than other wool, making it more comfortable, giving a softer feel and more airspace for moisture movement. Additionally, Merino wool ensures no-itch, while regular wool socks and apparel have tendencies for skin itch. Merino can also retain its shape longer than other wool.
Synthetic fibers have been engineered to have some important physical properties for athletic performance: water resistance, wicking, thermal insulation, wind resistance, anti-microbial resistance, durability, maintenance of shape when wet, quick drying, reduced weight, cushion and resiliency, reduced coefficient of friction, and odor resistance.
The most popular synthetic fibers used for sports socks are acrylic and polyester. Synthetic socks, made from acrylic, polyester (COOLMAX, Hollofil, Dacron, Thermolite), polypropylene, and nylon are supposed to wick moisture faster than wool and dry more quickly. Acrylic and polyester have several advantages over cotton fibers: they're hydrophobic, have superior wicking properties, and dry faster. In contrast to wool, synthetics feel damp when only a small amount of moisture is present. While both acrylic and polyester remain soft with multiple machine washings, resist wrinkles and stains, and retain their shape with moisture exposure, COOLMAX and other polyester fibers have a 15% faster drying time compared to acrylic fibers.
For summer hiking and/or in hot weather, polyester hiking socks (COOLMAX) are a better option than acrylic socks because, generally, acrylic provides poor insulation and, on hot surfaces, acrylic fiber socks can conduct heat. Additionally, some synthetics have been developed specially for cold conditions. Good examples of this are Thermolite and Hollofil. Designed to trap air, in a way similar to the way wool does it, they provide better insulation for your feet.
Avoid cotton in sports socks; it soaks up the sweat and then feels cold and clammy and takes a long time to dry. When wet it loses its shape and easily wrinkles, which is uncomfortable and can cause blisters.
Whatever the material, sweat-soaked socks should be changed for dry ones or your feet will be more likely to blister. Especially in hot weather, you need to change your hiking socks once or twice a day.
Hiking sock design and construction
A crew length sock is a standard hiking sock used all-year-round by many backpackers. The upper of the crew sock ends just below the calf muscle. The mini-crew design ends just above the malleoli of the ankle and is a popular choice primarily for summer hiking.
Example of sock designs: Crew sock (left), Mini-crew sock (right)
Densely knitted socks cushion better and feel more comfortable against the skin. In general, more expensive socks use more fabric and tightly woven knit patterns in their construction to provide maximum protection for the foot.
Ribbed legs with alternating thin and thick sections and elastic fibers in the leg or at the top of the sock keep the legs from sagging and slipping down. Good hiking socks are shaped at the heel (have a standard heel gore) for a good fit with no loose fabric as Y-Gore provides the best fit and conformity for the heel. Tube socks do not provide adequate fit since they have loose material around the heel that can slip and bunch up under your foot.
Some sports socks have different densities of material at different points for more cushioning or warmth. For instance, the foot of the sock can have a cushioned sole portion and cushioned instep portion. The arch section may have additional elastic for support. Some socks have an elasticized section over the instep, which helps with the fit.
The toe area of the sock has a seam that should be flat and smooth; it may be almost imperceptible in finer quality hosiery. The so-called seamless socks may benefit your feet by reducing pressure over the toes.
For cold weather, terry loops on the inside, especially underfoot, are warmer and more comfortable than flat knits. For warm weather, a flat knit over the foot and rib knit on the legs is cooler.
Whatever type of hiking socks you choose, make sure they fit well. Sock sizes often cover three or four shoe sizes, so you’ll need to check the chart on the package to find the size that should fit. Keep in mind that most socks tend to stretch over time, so if you hesitate between two variants, the smaller size is usually the better choice.
When putting on hiking socks, make sure the heel pocket is in the right place and that there’s no loose fabric anywhere. If there is, the socks don’t fit properly. Socks need to fit your footwear as well as your feet. Thus, for best results, you’d better wear your hiking socks when you fit your footwear.
Functions and benefits
One of the primary differentiating features of hiking socks, compared to casual socks, is the utilization of high-tech fibers and yarns. Today, the ordinary cotton sweat socks have been replaced with sports socks composed of synthetic fibers designed to provide better comfort and protection for the feet.
The conventional three-season backpacking sock system consists of two pairs. A thin liner sock is worn next to the skin. Its primary purpose is to manage moisture. Between the liner sock and the shoe, a thicker outer sock is worn to provide cushioning and insulation. However, wearing only a liner sock has some advantages too: they dry faster; absorb less moisture, and are cooler in three-season conditions.
Wet feet should not be a problem when wearing hiking shoes or boots for short periods. Lightweight hiking shoes and boots without waterproof breathable linings dry quickly when the air is dry. However, in prolonged wet weather, your footwear can stay wet for days. As a result, the skin of your feet gets softer, which can lead to blisters and sore spots. Waterproof hiking shoes and boots are suitable for cold conditions; however, in warm weather, these can be very hot and sweaty.
Waterproof breathable socks are much better than waterproof boots because they give more protection than boots. The reason is that waterproof hiking socks are much higher, some reaching just below the knee. In cold and wet conditions waterproof socks can work well, though the comfort range is too limited. When wet, they are slow-drying and not very durable.
In general, cotton fibers and most wool fibers are considered hydrophilic, while synthetic fibers are hydrophobic. Moisture can accumulate in the shoe from three different sources: the foot itself, the legs and trunk of the hiker, and the outside environment.
The production of moisture from the sweat glands of the feet during vigorous physical activity is estimated to be in the range of 2-2.5 liters per twenty-four hours. The production of moisture from the remainder of the body during exercise can exceed one liter per hour. Therefore, in order to keep moisture content at a minimal level on the surface of the foot during exercise, a sock must wick moisture (meaning transport moisture away to the shoe upper for evaporation).
Cotton fibers are hydrophilic and can absorb three times as much moisture as synthetic fibers. Moreover, cotton socks retain moisture and their drying time is much longer compared to synthetic socks. In a sedentary activity, cotton socks may be preferable to synthetic socks, given the low moisture output of the feet, and the better absorptive capacity of these hydrophilic fibers. However, during hiking or another physical activity, the absorptive capacity of any sock will be exceeded, and then you need moisture-wicking socks. They allow movement of moisture from the foot surface to the shoe for evaporation to the outside environment. When wet, acrylic fibers swell 5%, wool fibers swell 35%, cotton fibers swell 45%. Generally, swelling of fibers limits moisture transport and is related to a loss of shape and conformability to the foot.
Clinical benefits of sports socks
Being the closest layer of protection against the foot, socks have the potential to protect the skin and the deeper tissues from injury.
In walking and running, the primary stresses on the feet are impact, plantar pressure, friction, and shear. Impact forces result from gravity and inertia as the body propels forward. Plantar pressures are the result of impact, bone deformity, and biomechanical issues. Friction and shear occur when the foot strikes the ground tangential to the supportive surface and when the foot pushes off in propulsion. When external movement exceeds the frictional force at the skin interface, shear occurs where layers of skin begin to move upon each other. Initially, shear forces cause exfoliation of the stratum corneum on the skin surface but continued shearing forces can cause a cleft to develop, resulting in a blister.
Modern specialized sports socks can significantly reduce impact shock and plantar pressures on the foot. In addition, modern socks might mitigate shearing forces which result in friction blisters.
Friction blisters are considered the most common skin injury in sport. Because the sequel of these blisters can result in infection and disability, blister prevention has been of keen interest particularly in the United States Military.
Studies show that the establishment of a movement interface between the layers of a sock system will prevent skin injury as double-layer synthetic sock systems have been shown to be more effective than single-layer synthetic fiber socks in the prevention of blisters. The use of a polyester (COOLMAX) liner combined with a heavily padded wool/polypropylene-blended outer sock works out best for reducing the formation of blisters. Additionally, the fiber composition of the sock (it seems that synthetic fibers work best) may reduce the friction force on the skin surface.
Studies show that certain sports socks appear to be able to reduce moisture content on the feet during activity. This will minimize the chance of friction blisters. Damaging skin shear will also be minimized when thicker padded socks are worn, or when a two-layer synthetic sock system is worn. Other skin injuries such as calluses, corns, and toenail trauma may also be minimized by the wearing of proper sports socks.
When choosing socks for backpacking, keep in mind that specialized hiking socks may change the fitting requirements of the shoe. Heavily padded socks may require the addition of a full shoe size to allow proper room for the foot. The feet should be measured when you’re wearing the hiking socks intended to be worn during your hiking trip.
Good fit is difficult when socks are offered in sizes covering a broad range (greater than three shoe sizes) and that’s why premium sports socks are usually offered in narrow size ranges. Remember that sock sizes are not the same as shoe sizes.
In the case of chronic blisters, a double-layer or padded sock system is recommended. If there is no significant concern about skin injury, the selection of fiber may be more important than the construction style.
The socks marketplace is filled with products with consumer benefit claims such as blister protection, anti-microbial protection, and insulation which have not been scientifically substantiated. However, based on the best available scientific evidence, remember that:
- Cotton fibers are not recommended for construction and use in sports socks because of poor performance when exposed to moisture.
- Synthetic fibers have several advantages over cotton: they’re better at wicking moisture and also dry faster; they’re more durable and can maintain their shape when wet.
- Wool fiber socks, particularly Merino socks, have many positive characteristics of synthetic fibers. Wool hiking socks are superior to cotton socks in cold environments and have adequate wicking capacity to keep the feet drying.
- Padded socks are preferred to thin, un-padded socks because padding can protect the skin surface from friction and shear and can also significantly reduce plantar pressures and impact shock thus reducing the risk of feet injury.
- The use of a synthetic fiber liner sock, establishing a double-layer sock system, better reduce the incidence of blisters compared to single-layer sock systems.