This paper attempts to establish a correlation between bodily injury and the rate at which energy (power) is transferred to the body. Two head impacts are analyzed to demonstrate the procedures, however, analysis results are given for eleven head impacts. The methods involve the fundamental laws of mechanics and only the power levels are established empirically. Equations are developed that relate power to the absolute values of acceleration and the product of momentum and jerk. From the derived mathematical expressions a procedure for analyzing experimental data is given. The appendix contains a computer program for performing the analysis. Lastly arguments are given that predict the ideal processes for changing energy levels. Although the procedures described in this paper address only the human tolerances, it is conceivable the same procedure may be useful for analysis of inorganic structures.