Engineers at Georgia Tech and Emory University, have devised stairs that might one day do all the hard work involved in climbing up.
In a paper published today in the journal PLOS ONE, the team detailed their energy-recycling stairs, which stored energy when one descended, and then released it to make the ascent easier on the way back up.
One does not think about it while racing down a flight of stairs, but the body expends a considerable amount of energy in the process to prevent from falling.
The energy is usually wasted but these energy-recycling stairs take advantage of those forces using a spring-loaded mechanism that compresses each step and locks it down as while one descends.
Thus every step is charged with potential energy once one hits the bottom and when one goes to climb back up, pressure sensors on each tread release the locking mechanism on the step below it, turning that stored potential energy into kinetic energy that helps lift a climber's leg as the spring-powered step raises again.
As the stairs compress with one's descent, the engineers calculate that they saved around 26 per cent of the energy one normally used to brace oneself as each foot made contact.
On the way back up, the energy-recycling stairs made it around 37 per cent easier on the knee, making the stairs ideal for people who were pregnant, dealing with mobility issues, or were just simply out of shape.
The unique mechanisms of the stairs could be retrofitted to existing steps, so the technology could also be used in existing buildings.
Also installing the stairs would be cheaper, and require less space, than an escalator or elevator.