A device for measuring contractions and/or relaxation of one or more muscles of a body cavity, the device having a hollow body which is for positioning in the body cavity and which is covered by a coating made of or having a biocompatible material, the body being formed of two half-shells which are each physically connected, permanently and continuously during the use of the device, with the aid of non-compressible or deformable connecting means, to at least one pressure sensor, or part of the pressure sensor, arranged in the body. Also, a method for measuring the contraction and/or relaxation of the muscles of a body cavity, a method for monitoring the contractions and/or relaxation of the muscles, and a method for exercising these muscles.
