Angular acceleration is defined as the rate of change of angular velocity over time. Angular acceleration is generated from oblique angle impacts to the helmet’s surface and is particularly concerning to one’s health and long-term well-being. The medical community agrees that angular acceleration is a leading cause of concussion (a mild-traumatic brain injury (MTBI)), and traumatic brain injury (TBI). These types of injuries occur from oblique impacts to the helmet and are serious. The result of this type of impact, and subsequent energy transfer to the brain, is shearing, tearing, compression, and rotations of the brain within the skull.

Experiments conducted by David C. Viano, PhD. M.D. at the Bio-Engineering Center at Wayne State University confirmed that a helmeted head sustained the same degree of angular acceleration as the un-helmeted head when subjected to identical impacts.