A high-tech running shoe is worthless if it is two sizes too small and gives the runner blisters and pressure sores. The same goes for prosthetic limbs, according to David Sengeh, a 26-year-old graduate student from Sierra Leone who was honored Wednesday with an award for his work on an innovative socket that makes prosthetic limbs more comfortable and thus functional for amputees.

“Whether you have a robotic ankle or a wooden peg, if the socket is not functional you wouldn’t use your leg,” he told NBC News, explaining why he has focused his energy on developing next-generation sockets, or interfaces, for prostheses.