Neck injuries caused by rear-end collision are the most common injury type in motor vehicle accidents. The exact mechanism that causes whiplash is still not agreed upon. What has been agreed upon is that reducing relative movement between head and torso reduces neck injury. There are two ways to reduce relative movement between head and torso. One is supporting the passenger's head as fast as possible. Head acceleration is increased, reducing the relative acceleration between head and torso. This approach is the most common way to prevent whiplash injuries. The other way is to reduce torso acceleration by controlling the seat back and reducing the relative acceleration between head and torso. Based on benchmark test results, the second approach is an easy and robust way to handle the newly enhanced KNCAP test protocol. This study addresses a neck injury protection device to deal with enhanced neck injury rating systems in KNCAP & EURONCAP by controlling seat back frame movement. The device has been built, simulated, and tested.