The group of inventions relates to the field of measurements for the examination or analysis of the motion of the human body or of portions thereof for diagnostic purposes and specifically to determining a type of motion activity of a person. The implementation of the method involves recording signals from a three way accelerometer affixed to a person s body using said signals to calculate the modulus of an acceleration vector forming a time based array of values of the modulus of the acceleration vector and isolating the extrema thereof. Then proceeding sequentially from one extremum to another while counting a number of extrema equal to a reference number of extrema for at least one reference standard previously determined for a certain type of motion activity the duration of individual motion actions is determined and within the limits of each individual motion action values for the differences between neighboring extrema of the modulus of the acceleration vector are determined these are then compared with reference values for the duration of a motion action and the difference between neighboring extrema of the modulus of the acceleration vector of the corresponding reference standard. On the basis of the comparison results a decision is made that a motion was performed of a certain type of motion activity. The technical result consists in increasing the reliability of determining a type of motion activity of a person.