Wanna Run Faster? Get a Spring in Your Step!

High-tech footwear is making running more efficient and could eventually help us run more than 50% faster!

David Braun and Amanda Sutrisno (2020) at Vanderbilt University in Tennessee modelled the energy used during running and factors that can affect that, including air resistance, the limited power of a human leg and losses that occur each time a foot hits the ground.

They found that the leg only supplies energy about 20% of the time that the foot is on the ground. To improve on that, they have conceptualised a
spring-powered device that would increase the amount of power a person’s legs generate while running. It would allow the leg to supply energy 96% of that time, according to their analysis.

Braun and Sustrisno state that although “Humans have attempted to surpass their natural running capability using springs for at least a century”, springs do not provie external energy but have been shown to reduce the cost of walking by approximately 7.2% (+/- 2.6%).

The device would store energy created as the leg bends in the air, compressing the spring, and release it when the runner takes a step. The researchers analysed the running style of 100-metre world record holder Usain Bolt, who sprints at a top speed of 12.3 metres per second. The device
would in theory boost Bolt’s top speed to 20.9 metres per second.


Lu, D. (2020) Special Shoes Could Make You Run Faster. New Scientist. 04 April 2020, pp.21.

Sustrisno, A. & Braun, D.J. (2020) How to run 50% faster without external energy. Science Advances. 6(13), eaay1950. DOI: 10.1126/sciadv.aay1950.


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