A variable stroke engine includes a connecting rod having one end thereof connected to a piston via a piston pin. The valve member has an opening and is displaceable between an open position and a closed position. The method includes calculating a corrected activity energy expenditure data, if the raw activity energy expenditure data is associated with the high intensity physical activity, based on the raw activity energy expenditure data, wherein the corrected activity energy expenditure data is substantially identical to the expected activity energy expenditure data.