Abstract
The purpose of this study was to investigate the relationship between lower extremity strength and the ability to rise from a seated position in elderly patients.
The subjects were 205 elderly patients who were 65 years of age or older. They were classified into four groups according to their ability to stand up: those who were able to rise from a seat of 20 cm high, those able to rise from a seat of 30 cm high, and those able to rise from a seat of 40 cm high. Lower extremity strength was measured as isometric knee extension strength at the 90° angular flexion by a hand-held dynamometer. For analytic purposes, knee extension strength/body mass ratio was calculated. Age, height, body weight, Body Mass Index and isometric knee extension strength were analyzed. Logistic-regression analysis shows that knee extension strength is a critical factor affecting the ability to rise from a chair. Subjects with a knee extension strength of 35% or more were able to rise from a seat of 40 cm high. Subjects with a knee extension strength of 45 % or more were able to rise from a seat of 30 cm high, and subjects with a knee extension strength of 55% or more were able to rise from a seat of 20 cm high. On the other hand, subjects with a knee extension strength of under 20% were not able to rise from seat of 40 cm and 30 cm high, and subjects with a knee extension strength of under 30% were not able to rise from a seat of 20 cm high.
The results indicate that, for elderly patients, knee extension strength is an important factor for determining the ability to rise from a chair, and suggest that there is a certain threshold of knee extension strength under which no one can rise from a seated position.
