A spring-powered device that is attached to human legs could, according to a new US study, at least theoretically increase the sprint speed by more than 50% without external energy input.
Amanda Sutrisno and David J. Braun of Vanderbilt University say that such a (currently hypothetical) device would allow the wearer to deliver energy in the air by simultaneously compressing and increasing the stiffness of the springs.
During touchdown, the energy stored in the springs is released and the vertical impulse of the wearer is redirected to propel it forward.
“Our result uncovers the hidden potential of human performance enhancement through non-powered robot exoskeletons,” the researchers write in an article in the journal Advances in science.
“Our result could lead to a new generation of augmentation devices designed for sports, rescue and law enforcement agencies where people can benefit from faster movement speeds.”
According to Sutrisno and Braun, top athletes have reached a maximum running speed of 12.3 meters per second, but existing spring prostheses only allow a normal wearer to reach about 11 meters per second.
To investigate how human energy can be better used for improved running, they used a spring mass model with variable stiffness to predict the maximum speed an enlarged person can achieve without external energy, with air resistance and energy loss during the collision with the Soil are taken into account and limb performance restrictions.
Next, they predicted optimal relationships between running speed, spring stiffness, spring force, and ground contact time during high-speed running, and then designed a device in which springs support the body rather than the limbs and prevent energy loss through contact with the ground, similar to how wheels carry the frame of a bicycle.
There is a catch. Since even ultra-modern carbon fiber running springs do not have the required energy capacity, scientists would have to develop a new type of energy-tight spring in order to make ultra-fast, spring-powered people a reality.
However, Sutrisno and Braun are encouraged by how much speed in cycling and skating has increased thanks to technological advances.
RECOGNITION: Amanda Sutrisno and David J. Braun / Vanderbilt University