The present invention relates to a method (100) and system for evaluating a muscle related condition for a subject individual. The method comprises the steps of acquiring (101) a muscle quantity value (20) for the subject individual； acquiring (102) a data parameter value (10) for the subject individual, wherein the data parameter value relates to a quantified parameter of the subject individual's body composition； selecting (103) a number of individuals from a database (30) comprising at least one data parameter value (31) for a plurality of individuals and muscle quantity values (32) for said plurality of individuals, wherein the selection is based on the at least one data parameter value being compared to the subject individual's at least one data parameter value, thereby creating a virtual control group, VCG, (40)； calculating (104) a prediction value (50) of the muscle quantity values (42) for the individuals in the VCG (40)； and comparing (105) the muscle quantity value (20) for the subject individual to the determined prediction value (50) of the VCG (40).
