Foot-stiffening socks reduce running energy use by 2%

Researchers at the University of Texas at Austin have developed foot-stiffening socks that appear to reduce the energy required for walking and running. Owen Beck and Hui Tang, both affiliated with the university, created the socks by tightly knitting three millimetre-wide bands into a 30-millimetre region around the ball of the foot. This design applies 24 times more pressure to the feet than regular control socks, effectively increasing foot stiffness. The researchers note that human feet have naturally become stiffer than those of other apes over millions of years to support bipedalism, and their work explores whether further stiffness in footwear can enhance movement efficiency.

To evaluate the socks, Beck and Tang recruited 12 healthy adults of both sexes to walk on a treadmill while wearing the stiffened socks, control socks, or no socks. The team measured the participants’ VO2 max, the maximum amount of oxygen the body can absorb during high-intense exercise, to determine metabolic expenditure. The results showed that the foot-stiffening socks reduced metabolic expenditure by 2 per cent in 10 of the 12 participants compared to the control socks. The researchers state that this reduction is equivalent to the energy savings an average person would experience from losing two kilograms.

Beck explains that the socks work by allowing the ankle and its muscles to push off at a slower velocity, which requires less muscle activation and metabolic energy. Unlike stiffened shoes, which can restrict necessary foot movements at the end of a step, these socks permit the toes to flex and the arch to recoil more freely. Beck estimates that wrapping the foot in these new socks could improve marathon performance by one to two minutes, with hopes that elite runners might use them at the Los Angeles 2028 Olympics. He also suggests that the reduced whole-body metabolic rate could lead to better walking endurance and less sweating on hot days.

While the findings are promising, independent experts have offered cautious perspectives. Thomas Püschel at the University of Oxford notes that the idea of a stiff foot reducing metabolic cost has long existed, but previous attempts using stiff midsoles or inserts in shoes failed because they prevented necessary foot movement. Püschel warns that other explanations for the results cannot be ruled out, such as volunteers altering their gait because they knew they were wearing the socks. He describes the study as a promising first demonstration rather than definitive evidence that the socks will change daily life.

The research team has a sponsored research agreement with shoe company New Balance to commercialise the socks. Beck suggests that in theory, anyone whose feet have lost some of their shape, such as through old age, could benefit from the technology. The study was published in the Royal Society Proceedings B.