Details of a new crash simulator and preliminary results from a series of cadaver knee impact experiments were presented at the Eighth Stapp Conference. During the past year additional data concerning injury to the knee-thigh-hip complex have been obtained, and the studies have been extended to consider impact to the chest. Results to date indicate that for knee impacts against a moderately padded surface it is not possible to predict whether failure of the patella, femur or pelvis will occur first, although in these studies femoral fractures occurred most frequently. A force of 1400 lb. is recommended at this time as a reasonably conservative value for the over-all injury threshold level. Volunteers tolerated impact loads to the knee of 800-1000 lb.

For loads applied over the sternum through a 25-30 padded surface, static and dynamic thoracic stiffness characteristics were determined for a limited number of cadavers. In two cases the dynamic force-deflection relationship was linear with a slope of approximately 1000 lb./in. up to 900 lb., where indications of skeletal damage were manifested. Volunteers tolerated similarly applied static loads of 300-400 lb.