The aging mover: a preliminary report on constraints to action. 
Locomotion by older adults is typically characterized by performance declines.  Older individuals walk more slowly, take shorter steps, and spend a longer time in support than young individuals.  Investigators assumed implicitly that declines are related to an inevitable aging process.  The purpose of this investigation was to examine constraints that might result in the declines described, outside or in addition to, the general process of aging.  We examined two types of terrain over which locomotion might occur, level ground and stairs, and two movement speeds, preferred and fast.  Healthy, active females between twenty to eighty years were videotaped.  Individuals over sixty years walked at significantly slower speeds, particularly climbing stairs.  They used a smaller range of speeds than younger individuals.  Despite this slowing, the pattern of coordination between limbs remained essentially the same across the ages tested.  The small magnitude of declines observed was attributed to the good health and active lifestyles of these individuals.