KINEMATICS OF THE YOUNG-ADULT AND OLD-ADULT LOWER LIMB DURING STAIR ASCENT AND STAIR DESCENT

Abstract

High levels of energy expenditure while stairclimbing have been well-documentedand sedentary beings have been advised to opt for the stairs over the elevator because of the aerobic workout that the activity demands (Koszuta, 1987). Few systematic attempts (e.g., Horna & Hudson, 1991; Williams & Bird, 1992) have been made, however, to quantify the motion of subjects while ascending or descending stairs. The manner in which a staircase may be climbed, and hence the sense of comfort experienced, may vary considerably depending upon the constraints (i.e., organism, environmental and task-related) imposed upon the climber (Clark, 1995). Some (e.g., Perlin, 1992) have questioned the feasibilityof this form of exercise for older adults. The purpose of this investigation was toreplicate an earlier study (Livingston et al., 1991) of young-adult lower-limbkinematics with an older-adult population. Five physically active, older-adult women with a mean age of 67.4 years (SD=6.5) each completed ten trials of free speedstair ascent and stair descent over three staircases. Data for the five older adult subjects were captured via high-speed cine cameras and switchmat/timerdevices and were matched (by subject height) with data for five fit and healthy young-adult women from the previous study. The results of a mixed between within repeated measures MANOVA yielded several significant results. During stair ascent, the older-adults tended to climb the stairs using slower cadences and longer cycle times, yet elderly stance (48% to 59%) and swing (41% to 52%)values did not vary significantly from those of the younger adults (52% to 55%and 45% to 48%, respectively). During stair descent, however, stance phase durations for the control group varied considerably (20% to 53%) depending upon the staircase climbed, while those observed for the elderly (50% to 57%) varied little. These differences were significant (i.e., between groups (F(1,8)=26.80,pc0.01, within groups (F(2,7)=35.71, p<0.01), and an interaction effect was observed (F(2,7)= 16.17, pc0.01). The observed differences may be explained by the slower movement velocities and reduced variability in joint ranges of motion for the lower limb observed in the older adults. Provided that the older adultstair climber does not suffer from any locomotor impairments or balance problems, stairclimbing as a form of aerobic exercise would seem to remain a viable option.