Socks with tight bands around the ball of the foot reduce the energy needed for walking and running, according to research by Owen Beck and Hui Tang at the University of Texas at Austin. The effect matches the energy savings of losing 2 kilograms, the researchers found.
Beck and Tang knitted three 1-millimetre-wide bands into a 30-millimetre-wide region around the ball of the foot using common synthetic yarn. This creates 24 times more pressure than regular socks. In tests with 12 healthy adults, the foot-stiffening socks reduced metabolic expenditure by 2 per cent more than control socks in 10 of 12 participants.
Beck estimates the socks could improve marathon performance by 1 to 2 minutes. The socks work by letting the ankle muscles push off at slower velocity, requiring less metabolic energy and producing more economical muscle contractions. Unlike stiffened shoes, the socks allow toes to flex and the arch to recoil freely.
Thomas Püschel at the University of Oxford noted that earlier attempts to reduce energy cost through stiffer shoes failed because they stopped the foot moving when it needs to at the end of each step. The new sock design avoids this problem.
Beck says the socks could theoretically benefit anyone whose feet have lost shape through age. New Balance has a sponsored research agreement with Beck and Tang to commercialise the socks. Püschel cautions that other explanations for the results, such as participants changing how they walked when aware of the socks, cannot be ruled out. He calls it a promising first demonstration rather than proof the socks will change daily life.
The research was published in Royal Society Proceedings B.