An exercise apparatus and method for exercising at least a user’s abdominal muscles is provided having a support frame, a platform pivotally connected to the support frame and having means for tilting the platform relative to the frame between a forward tilting position and a rearward tilting position. The first interface communicates with the peripheral device over a differential data connection having a first data conductor and a second data conductor. In some embodiments, the machine has no unconstrained RAM into which malware may insert itself and needs no anti-virus software. The object of the invention is to provide improved footwear as referred to in the introduction, as well as improved spring means according to the invention, with on the one hand small constructional dimensions whilst retaining an advantageous spring effect, which is furthermore easier to adjust.