RESULTS: Mean value for male and female patients combined was 70.2±7.7 years for age, 68.2±12.6 kg for weight, 26.3±4.1 kg/m2 for body mass index (BMI), with a forced expiratory volume in 1 second (FEV1) of 45.2±19.1%. FFM was higher with Rutten formula compared to other formulas. Statistical analysis considered gender, age, weight, BMI, FFM, FM and percent body fat as potential determinants of muscle function. Coherent results were obtained using the four disease-specific formulas. HGS, MIP, MEP and 6MWD were all more strongly correlated with body composition than with age and subjects’ basic physical characteristics. Determinants emerged from multiple regression analysis as follows: gender, age and FFM for HGS; age and FFM for MIP and MEP; percent body fat and FFM for 6MWD. The proportion of variance explained was much higher for HGS than for other tests.