Rising from a chair: effects of age and functional ability on performance biomechanics.

Although difficulty in rising from a chair is common to elderly people, few studies have compared chair rise performance in young and elderly adults with differing functional abilities. Using an instrumented chair and a videotape analysis, controlled chair rise performances were quantified in three groups of volunteers: young adults (Young, n = 17, mean age 23 years), elderly adults able to rise without the use of armrests (Old Able, n = 23, mean age 72 years), and elderly adults unable to rise without the use of armrests (Old Unable, n = 11, mean age 84 years). Rises both with and without the use of hands were observed. The total time to rise and the percent of that time spent in the two distinct phases of the rise, the body segment rotations used, and the hand forces exerted were measured. Despite no apparent functional impairment, the Old Able compared to the Young spent a larger percent time in the first phase of the rise and rotated their body segments by different amounts. When rising with use of hands, the Old Unable compared to the Old Able group took more time and used different body segment rotations and larger ratios of hand force to body weight. These data quantify chair rise performance in young adults and in elderly adults with differing functional abilities and enable biomechanical analyses of the importance of joint torque strengths and postural stability in that performance.