Golf device and method

A method of monitoring the performance a sportsman performing a plurality of motor acts, the method comprising:

• attaching a portable main device containing at least a timing device, a signal processing unit, a computing unit and a display unit, to a body part of the sportsman,
• attaching an external sensor unit to an object used by the sportsman in said motor acts, the sensor being responsive to movement and arranged to generate a sensor output signal,
• wherein the portable main device and external sensor unit comprise wireless communication means adapted to enable wireless communication of the sensor output signal from the external sensor to the main device,
• wherein the method further comprises:
• extracting data on the course of each of the motor acts from the sensor output signal in said signal processing unit, the extracted data including key time points of the motor acts,
• computing at least the statistical deviation of a series of repeated motor acts of said sportsman, using said extracted data from the signal processing unit, and based on the repeatability of said motor acts, calculating a handicap value predictive of the performance of said sportsman and
• displaying said calculated handicap on the display unit.