Certain embodiments of the invention provide an exercise device for limb exercises comprising: means for detecting a force applied to the apparatus； and means for sliding the exercise device along another surface separate of the exercise device. A system is also provided which comprises the exercise device with one or more sensors which are remote of the exercise device for sensing at least one of movement, acceleration or orientation. Furthermore, a computer program is provided for receiving, at a remote device, a signal transmitted from the exercise device and generating an output dependent upon the received signal.
