Yoshida et al reported equations for estimating appendicular skeletal muscle mass in older Japanese adults. The authors are from the Center for Gerontology and Social Science, National Hospital for Geriatric Medicine, National Center for Geriatrics and Gerontology and Japan Foundation for Aging and Health in Japan.

Patient selection: Japanese adults >= 65 years of age


Analysis: bioelectrical impedance analysis (BIA)



(1) sex

(2) height in cm

(3) weight in kilograms

(4) resistance at 50kHz in Ohms


impedance index =

= ((height)^2) / (resistance)



• The impedance index is referred to as the resistance or resistive index by other authors.


appendicular muscle mass for a male in kilograms =

= (0.197 * (impedance index)) + (0.179 * (weight)) - 0.019


appendicular muscle mass for a female in kilograms =

= (0.221 * (impedance index)) + (0.117 * (weight)) + 0.881



• The R^2 for males is 0.87 and for females is 0.89.

• The standard error of the estimate for males is 0.98 kg for males and 0.81 kg for females.

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