The invention relates to a bending sensor for detecting function parameters for the characterization of motion sequences at the human or animal body. The bending sensor comprises a fixing element 20, in particular a fixing plaster, for fixing the bending sensor on the skin of the human or animal body. Furthermore, a bending-sensitive detector 10 for detecting bending parameters of the bending sensor is provided. The detected bending parameters such as, for instance, the bending angle, the bending rate, and/or the bending acceleration are stored in a data memory 30. The fixing element is extensible and comprises an extensible cavity for accommodating a measuring sensor of the detector. The measuring sensor is fixed at a reference point of the fixing element in the cavity.