Table 1 Equations used in calculation of Skeletal Muscle Mass (SMM) using bioelectrical impedance analysis. In both equations: Height in cm; Sex 1 = male, 0 = female; Weight in kg; Resistance in Ω; Reactance in Ω

SMM-Sergi [11]

= −3.964 + [0.227 × (height²/resistance)] + (0.095 × weight) + (1.384 × Sex) + (0.064 × reactance)

SMM-Janssen [10]

= [(height²/resistance) × 0.401] + (Sex ×  0.3825) + (Age × − 0.071) + 5.102

Phase angle

= arctan (reactance/resistance)

“arctan” is the inverse trigonomic function (arc tangent) of the tangent function