Janssen et al used bioelectrical impedance analysis (BIA) to estimate the skeletal muscle mass in adults. The authors are from Queen's University (Kingston, Ontario), Columbia University (New York City) and the University of New Mexico.


Patient selection: healthy adult



(1) height in centimeters

(2) resistance in ohms from BIA

(3) age in years

(4) gender (1 if male, 0 if female)


skeletal muscle mass in kilograms =

= (0.401 * ((height in cm)^2) / (resistance)) + (3.825 * (points for gender)) - (0.071 * (age)) + 5.102



• The equation was developed in Caucasians, It was found to be applicable to Blacks and Hispanics. It tends to underestimate muscle mass in Asians.

• R-squared was 0.86 and SEE 2.7 kg.

To read more or access our algorithms and calculators, please log in or register.