A simple pair of socks could make walking less tiring without changing the way we walk.
The principle is remarkably simple: these socks squeeze the front of the foot more tightly, near the base of the toes. This pressure prevents the foot from spreading too much when it supports the body's weight. The arch of the foot, the curve beneath it, thus becomes stiffer.
A person walking.
cottonbro studio · Pexels
With every step, our foot deforms under our weight, then allows us to push against the ground. The calf muscles contribute to this movement. Slightly changing the way the foot bends can therefore alter the effort required from the muscles, even if walking appears unchanged.
To test this, Hui Tang and Owen Beck, from the University of Texas at Austin, recruited twelve healthy young adults. Each person walked on a treadmill at an ordinary speed while wearing two types of socks. One type had tight bands, while the other served as a comparison. The researchers also filmed the participants' movements.
The result was modest but measurable: the reinforced socks reduced the energy required for walking by an average of 2%. Ten of the twelve participants benefited from this reduction. The scientists calculated this energy expenditure from the oxygen consumed and carbon dioxide released during exercise.
Compression sock test
One might think that the socks save energy simply by reducing the work done by the legs. However, the measurements indicate a different mechanism. The calf muscles contract more slowly, under conditions in which they use less energy. The movement that allows the foot to push against the ground remains intact.
To give a sense of scale, the authors compare this gain to that obtained by removing about 2 kg of weight carried around the waist.
This experiment also offers a clue about the history of our bodies. The human foot is generally stiffer than that of other primates. This characteristic may have favored efficient two-legged walking over the course of evolution. The socks make it possible to test this hypothesis directly, without permanently modifying the foot.
It remains to be seen whether the gain persists during long walks, on uneven ground, or in older people. The study involved only twelve adults and treadmill trials. Longer tests will also need to determine whether this additional support remains comfortable in everyday life.