The objective of this proposal is to continue research and development of a cost-effective device that measures linear and rotational head acceleration following impact in sports. Mild traumatic brain injury (MTBI) in sports is a significant public health concern. The biomechanics of head impacts that result in a concussion or other MTBI are not well understood but are widely believed to correlate with head accelerations. The lack of a system that allows researchers to measure head acceleration during actual play in a large number of individuals is a major obstacle in furthering our understanding of the mechanism of MTBI and its prevention. A novel algorithm for calculating linear and rotational acceleration of the head was developed and will be incorporated in a miniature accelerometer-based telemetry data acquisition system. Clinical trials will be performed at two major colleges over the course of a season in men's football and men's and women's hockey. The trial will be performed in conjunction with ongoing head injury studies that include neuropsychological testing of athletes, and neuropsychological test scores will be analyzed. The long-term goal of the project is to develop a cost-effective commercially available system for measuring head acceleration for widespread use in sports.