The death last week of boxer Patrick Day, four days after he was stretchered out of the ring in a coma, is the latest reminder of how vulnerable sportsmen and women are to traumatic brain injury. During the latest Ashes series the Australian batsman Steve Smith was temporarily retired for one test after being struck on the helmet by a bouncer. The current World Cup Rugby has been affected too, with Welsh fly half Dan Biggar withdrawn from a game against Uruguay having received head injuries in two previous matches.

In this edition of Discovery, Roland Pease talks to engineers at Imperial College and Loughborough University using the latest techniques to understand the dynamics of blows to the head, and to improve helmet protection. And to experts and Rugby players at Swansea University seeking to make precision measurements of real-life head movements with the help of gum shields stuffed with electronics.

Picture credit: Mazdak Ghajari