Rising from a chair. Influence of age and chair design.

We studied the effect of age on the act of rising from a standard armchair in a younger (means = 24 years) and an older (means = 75 years) group of healthy adult women. Rising from a standard armchair and an armchair specially designed for comfort in sitting of the elderly was studied in the older group to determine the influence of the special chair. We used electrogoniometry, EMG, and videotape analysis to record the activity for both groups. The older group placed their feet farther back and showed greater vastus lateralis muscle activity than did the younger group to rise from the standard chair. These results suggest that rising from the standard chair was more difficult for the older than for the younger group. In the special chair, the older subjects showed even more vastus lateralis muscle activity, greater knee flexion, and greater trunk forward lean. Rising from the special chair, therefore, appeared to be more difficult than rising from a standard chair; this finding suggests that both comfort and function must be considered in chair selection for certain groups.