Abstract: The restraining inflatable neck guard is adapted to be located around a person's neck when deflated. A source of compressed gas is coupled to the neck guard for inflating the guard. A normally closed electrically actuated valve is provided for releasing the compressed gas from the source for flow to the inflatable neck guard when actuated. A sensor is provided for sensing acceleration/deceleration forces in three mutually perpendicular directions and for producing electrical outputs having levels which are proportional to the forces sensed. A threshold device compares the electrical outputs with a threshold to actuate the valve when either of the electrical outputs reaches the threshold. The sensor may be employed to sense acceleration/deceleration forces in one direction only. Aircraft or vehicle systems may be used to initiate the inflation sequence. The restraining inflatable neck guard is designed to maintain distance between the neck and collar throughout the inflation process.