s 497 EFFECTS OF RUNG SPACING ON THE MECHANICS OF LADDER ASCENT D. R. MCINTYRE (Biomechanics Lab., North Texas State University, Denton. TX) and B. T BATES (Biomechanics/Sports Medicine Lab., University of Oregon. Eugene, OR) Twenty male subjects grouped according to their standing heights, each performed 3 climbing trials. Each trial corresponded to one of three selected rung spacing conditions. Temporal, kinematic and kinetic measures of each performance were recorded. Significant temporal differences were found between the rung spacing conditions. The kinematic analysis revealed characteristic movement patterns displayed by each limb segment for each condition. The kinematic analysis showed that the primary role of the hands was for the maintenance of stabili ty in a direction perpendicular to the ladder uprights with the magnitudes of the forces being subject group dependent. The primary role of the forces directed through the feet was found to be for the vertical elevation of the body. Abnormalities in the temporal, kinematic and kinetic characteristics of the gait cycles were related to an increased potential for the occurrence of a climbing accident. CORRELATION OF DEGREE OF INDUCED CONCUSSION WITH THE DEGREE OF EXCITATIOU OF RESONANT FREQUENCY. RESULTING FROM HEAD IMPACT IN THE STUMPT.*IL MOVtiE1 f MACACA SPECIOSA I JOHN E. KOI-WICK (Pleasant Ridge, MI) Some investigators of head impact trauma have suggested that resonance of the head may contribute IO the severity of the trauma. Todetermineifsuch a correlation does exist, thedata from impacts to the heads of6 female stumptail monkeys were analyzed. The animal’s heart rate and respiration were recorded to assess the duration of an induced concussion, and the acceleration-time history from a calvarium-mounted accelerometer was Fourieranalyzed to determine the energy level at the surrogate’s reasonant frequency of 1700 Hz. Little correlation was exhibited when either the rise-time only portion of the acceleration-time history was analyzed. or the full pulse wave form was statistically analyzed. BIOMECHANICAL ANALYSES OF LOAD LIFTI’iG A. FREIVALDS, D. B. CHAFFIN and K. S. LEE (Industrial and Operations Engineering. The University of Michigan, Center for Ergonomics. MI) To better understand the effects of load and posture on joint torques, the motion dynamics of 6 subjects lifting maximum loads in 4 different types of containers from floor to table height were examined. Jomr center coordinates from photographs, ground reaction forces from a force platform and EMG from the erector spinae at the L, S, joint were analyzed and entered into a 7 link, dynamic biomechanical model. Container size shoaed little effect. Containers without handles produced slower rise times and smaller peab ground reaction forces as opposed to containers with handles, indicating more controlled movements. Smoothed and rectified EMG showed similar responses having good correlation with the ground reaction forces. These records also allnaed Lalidation of low back compressive forces as calculated by the model.