Abstract: Mathematical model of human body has been developed based on ejection tests. Combining vertebral breaking strength with dynamic response characteristics of the model, human's tolerance limits of acceleration have been determined. The model is used to study the effects of ejection cushion and !a thin cushion is recommended for avoiding vertebral injury. How to improve the ejection propeller and to determine the requirements of acceleration measuring system are discussed. To put the mathematical model in practice is convenient, safe and useful for human being.

Key words: ejection acceleration, mathcmatical model, tolcrance, dynamic response of human body, ejection cushion