Relationship between leg muscle strength and standing ability or walking ability in elderly people

The purpose of this study was to examine the relationship between leg muscle strength and standing ability or walking ability in elderly people using cross-sectional data. Independently living elderly people who were 60 years or older(n=1041, Male 344, mean age 74.6 years, Female 697, mean age 72.3 years) volunteered to participate in this study. The functional fitness (Standing, Walking, Hand working, Self-care working) and leg muscle strength (knee joint extension in isometric contraction) were measured, and also pain on lower extremity (lumb, hip joint, knee joint, ankle joint) was examined by medical doctor or public health nurse. Multiple regression analysis for relationship between leg muscle strength and standing ability or walking ability in elderly people was performed. Standing ability or walking ability was used as the dependent variable, and leg muscle strength as the independent variable. Age and the pain of lower extremity were adjusted for the relationship as confounding factors. The results were as follows; 1) In both male and female, the simple correlation coefficients between age and leg muscle strength (male r= -0.458 p<0.01, female r=-0.295 p<0.01), standing time(male r=-0.633 p<0.01, female r=-0.548 p<0.01) or walking time (male r=-0.636 p<0.01, female r=-0.591 p<0.01) showed significant relationship, respectively. 2) In both male and female, the simple correlation coefficients between the leg muscle strength per body weight and standing time (male r=-0.499 p<0.01, female r=-0.440 p<0.01) or walking time (male r=-0.545 p<0.01, female r=-0.430 p<0.01) showed significant relationship, respectively. 3) In both male and female, multiple regression analysis showed significant the relationship between the leg muscle strength per body weight and standing time (male β=-0.263 p<0.001, female β=-0.303 p<0.001), and significant the relationship between the leg muscle strength per body weight and walking time (male β= -0.319 p<0.001, female β=-0.280 p<0.001). These results showed that strong leg muscle strength shows high standing ability and high walking ability independently with age and the pain of lower extremity. Therefore, it was suggested that the maintenance of leg muscle strength might to prevent the decline of standing and walking ability.