A device for reducing traumatic brain injury comprises a first sensor, a first linkage element, and a processing element. The first sensor is coupled to a head component and configured to measure an acceleration of a user's head and to generate a sequence of real-time measured samples. The first linkage element is configured to connect the head component to a body component and is able to switch between a first state in which it is relatively flexible and a second state in which it is relatively rigid. The first linkage element is switched from its first state to its second state by a locking signal. The processing element is configured to receive the real-time measured samples and to generate the locking signal when each of a portion of the real-time measured samples is greater than one of a corresponding portion of a plurality of dynamic concussion thresholds.