STUDY OF IMPACT TOLERANCE THROUGH FREE-FALL INVESTIGATIONS

Abstract

The study has combined techniques of detailed investigation of selected human free-fall impacts and computer simulation of representative falls in order to expand knowledge of human impact tolerance. Of 2100 falls occurring in the U.S. and Canada, 110 cases were selected for on-site investigation of biomedical and biophysical factors. Seven head-first, two side-first, and three feet-first falls were then simulated using the MVMA 2-D Crash Victim Simulator. Children were generally injured less severely than adults under similar fall circumstances, and tended to land on their heads a greater proportion of the time. It was found that survival limits for children may be higher than previously believed. Body position at impact was a major factor in resulting injuries. In falls to rigid surfaces certain types of injury can be predicted on the basis of age and fall distance. For children under age 8 it is concluded that a constant acceleration of up to 350 G for 2.5-3 msec approaches the survival limit for head impacts. For children younger than 18 months the minimum limit tolerance level for reversible head injury may be reached when fall distance is somewhat greater than four feet.