Method and system for determining the speed of a walking or running person from a foot motion. The method comprises providing (1) a pressure sensor between the foot and the ground, which sensor may be placed on or in an insole of a shoe. The pressure sensor is configured for transmitting pressure data to a communication unit (9). The method further comprises a step of determining a center of pressure gait line (3) and calculating the center of pressure speed (4) from the gait line. In addition, the method comprises the step of detecting whether the person is walking or running (5). Another step (6) is obtaining a correlation between the speed of a person and the center of pressure speed. As a final step (7) of the method the speed of the person is deduced from the correlation. The system comprises a human interface for control and to inform the user.