Modern (non-MIPS) helmets are wonderful pieces of technology in terms of their impact resistance. They are designed – and tested – to help prevent skull fractures and other major blunt-force trauma. They are not, however, designed to mitigate the forces that can cause a concussion.
A Swedish company called Multi-directional Impact Protection System (MIPS) patented the slip plane concept (what it calls a low-friction layer), using two layers in the helmet (the MIPS “liner”) to help mitigate the rotational force of an impact, which can result in a concussion or other brain injury. Here’s how the company itself describes the technology:
“In a helmet with MIPS Brain Protection System the shell and the liner are separated by a low friction layer. When a helmet with MIPS Brain Protection System is subjected to an angled impact, the low friction layer allows the helmet to slide relative to the head.”