The purpose of this study was to examine the effects of different surfaces on lower limb motion and encountered pressures at two locations on the plantar surface of the right foot. Nine females performed five trials for each of four surface conditions. The results provided no evidence for surface-related changes in experienced foot contact pressures. Both asphalt and grass surfaces resulted in the shortest relative time of forefoot immobility. No surface related differences were found for the range of pronation.

In this study, the relationship between maximal aerobic capacity (VO₂max) and left ventricular function was examined in two distinct age groups. A young group (20 - 30 years of age) and an elderly group (over 60 years of age) were compared. Left ventricular function was examined over wide variations in preload accomplished by 5º head-down tilt (TILT) for ninety minutes and lower body negative pressure (LBNP) to -40 mm Hg. with two-dimensional echocardiography. A greater response to an increase in preload (TILT) was related to high VO₂max levels in the young subjects but not in the elderly groups of subjects, suggesting that lower VO₂max levels of the elderly population affected the mechanism of response to the increased levels of preload. Additionally, in the elderly, greater reductions in ventricular volume reflected increased peripheral pooling due to decreased venous tone and/or increased venous compliance during LBNP and were related to increased VO₂max. In the young, VO₂max does not appear to affect the response to reduced preload.