The present invention relates to a method for estimating the physical activity exerted by an upper limb (10) of a person (1), the method being characterised in that it comprises the steps of: (a) acquiring, by inertial measurement means (20) rigidly attached to a forearm (11) of said upper limb (10) of said person (1), an angular speed of said forearm (10) (b) estimating, by data-processing means (21, 31, 41), a torque exerted by the arm muscles (12) of the upper limb (1) on said forearm (11) as a function of the measured angular speed, of an orientation of said forearm (11) and of physical parameters of said forearm (11) (c) determining, by a data-processing means (21, 31, 41), a power exerted by the upper limb (10) as a function of the estimated torque and of the measured angular speed.
