The concept of increasing strength requirements for automotive seats has been proposed as a means of reducing occupant injuries, particularly in the rear-end impact environment. This paper will evaluate various safety trade-offs and practical requirements of seat design brought about by modifications that include the rigidification of seat structures. Rigidified and yielding seat design concepts are evaluated, utilizing analytical procedures as well as data from static and dynamic tests. The effect of seat rigidification is examined in terms of occupant interaction with the surrounding structure and with the restraint system. Potential effects of these modifications on occupant kinematics and resulting injury exposures are also examined. The elastic properties of conventionally rigidified seat structures are compared to rigid seat structures in terms of their effect on occupant motion during collision. Various crash types are evaluated in terms of occupant protection potential relating to seat collision performance; however, the design emphasis is on the rear-end collision exposure.