System and method for measurement of cardiorespiratory fitness of a subject

A computer-implemented method for determining a cardiorespiratory fitness measurement of a subject, comprising:

• receiving a stream of signals outputted by a sensor unit comprising one or more motion sensing modules,
• determining, from the signal stream, a kinetic energy data stream, KEDS, for each non-exercise period (N) of an exercise session (E) for gradually increasing the oxygen consumption, VO2, of the subject, wherein the exercise session (E) comprises a plurality of alternating exertion segments (S) and non-exercise periods (N),
• for each non-exercise period (N):
• obtaining a mean kinetic energy (MKE) that is a time-averaged kinetic energy value from a time window (W) of the kinetic energy data stream, KEDS;
• determining multiple mean kinetic energies (MMKEs), for different time windows (W);
• determining an order statistic (OS) from the multiple mean kinetic energies, (MMKEs)
• determining a set of order statistics (SOS) containing at least some of the order statics (OS) determined from the plurality of non-exercise periods (N) of the exercise session (E);
• determine from the set of order statistics (SOS), the cardiorespiratory fitness measurement of the subject.