s 493 tubes in helical, serpentine, forward and reverse spiral and woven (macrame) Patterns: steady flow with superimposed simple harmonic oscillations (various amplitudes and frequencies) was used as the pulsatile flow. The mass transfer coefficients for O2 and CO, show that with all of these curvature patterns and for the range of Dean and Womersley numbers involved, the transport is correlated best with the magnitude of the oscillatory velocity, and that in a tubing enhanced transport, the pattern ofcurvature is less important than curvature itself; repeated reverses of curvature as in woven patterns do not cancel the benefits of curvature. ON PARACHUTIST DYNAMICS ROKALD L. HUSTOX and JAMES W. KAMMAK (University of Cincinnati, Cincinnati, OH) Results of a computer simulation and a parameter study are presented. A variety of initial parachutist configurations prior to ‘opening shock’, are considered and the relative effects on the parachutist’s dynamics particularly, the head/neck system dynamics are studied. Optimal initial (pre-opening) configurations. which minimize the subsequent force and moment pulses experienced by the head/neck system, are identified and discussed. Application in parachute design and in developing jumping strategies is also discussed. RESPOYSE OF A SIMPLIFIED INTERVERTEBRAL DISC MODEL USDER COMPLEX LOADI\G R. L. SPILKER and D. M. DAUGIRDA (Department of Materials Engineering, University of Illinois at Chicago Circle, Chicago, IL) A simplified axisymmetric finite-element model of the vertebral body-intervertebral disc is described which employs three homogeneous substructures corresponding to the vertebral body/endpIate region, the annulus fibrosis of the intervertebral disc, and the nucleus pulposis. The first two regions are modelled as istropic materials with the vertebral body/endplate region treated as nearly rigid compared with the annulus. The nucleus is modelled as an incompressible, inviscid fluid. The response of the model to compression, torsional. shear, and moment loadings is examined. A Fourier series representation of circumferential behavior allows the analysis to be reduced to a 2-dimensional model for each loading case. The model is used to examine the effects ofgross disc geometry and material property parameters on predicted intradiscal pressure increase. disc bulge, and other pertinent displacement quantities. The results obtained indicate that all parameters have a significant effect on disc displacements. Only compressive loading produces increases in intradiscal pressure, and these pressure increases are most strongly affected by changes in disc height and radius. For torsional and moment loading, predicted displacements are shown to correlate reasonably with strength of materials solutions. Results obtained with this simplified model are also shown to be in reasonable agreement with published experimental measurements, with appropriate choice ofmaterial property parameters. MASS DENSITY DISTRIBUTlON ALONG THE BODY AXIS H. K. Ht ANG, PETER WEISS, D. D. ROBERTSON and F. R. SCAREZ (Department of Physiology Kc Biophysics, Georgetown University Medical School, Washington, D.C.) The purpose of this paper is to report on data of the distribution of various physical properties along the body axis. This data was generated using the computerized tomographic scanning technique, Five cadaveric specimens, ranging in age from a newborn infant to a 7-yr old child, have been studied usmg this method. Each specimen was scanned from the head to the ankle joints at 1 cm increments, Each CT scan produces a cross-sectional image of the body cross-section under consideration. The CT image can then be related to the mass density distribution ofthe scanned section. Using standard picture processing techniques and formulae for discrete masses in mechanics. the mass, area, specific gravtty. geometrical center. center of gravity. and inertia tensor for each cross-section are estimated. For each parameter, the sectional quantity vs the body axis can be plotted, demonstrating the disrributlon of the parameter along the body. (This research is supported by NHTSA, Department of Transportation. Contract No. DOT-HS-7-01661.) H. K. Huan8 cr nl.. Utilization of CT Scans as Input to Finite Elements Analysis Proc Intern Finite Elements In Biomechanrcs. Feb. 18-20, 1980, pp 797-816. IYFLUENCE OF THREE-DIMENSIONAL GEOMETRY ON SIJCCESS I THE BENCH PRESS N. MADSEX (Department of Mechanical Engineering) and T. MCLAUGHLIN (National Strength Research Center, Interdisciplinary Biomechanics Laboratory. Auburn University. Auburn, AL) In recent years the increased incidence of musculoskeletal injuries in the population due to bench presses served as motivation for detailed analysis of this motion. Kinematic 2-D studies of 13 1 world-class and beginner subjects