Device and method for monitoring the performance while swimming

The invention relates to an apparatus and a method for monitoring the execution of swimming. The device comprises one or more motion sensitive sensors for providing motion data that are characteristic for the movement of the float when executing the swimming exercise and a calculation unit adapted for detecting body movements from the movement data using pre-defined criteria. According to the invention, the calculation unit includes means for calculating a plurality of correlation factors, the motion correlation data between successive detected body movements reflect, means for storing the correlation factors as a temporal sequence, and means for determining one or more parameters which are characteristic of the floating-type, based on the stored correlation factors. The invention can be used for example for a robust determination of contact of the float, a distance swum or the swimming style.