An exercise machine for providing a low impact workout that targets the core muscles. The cross-sectional area of the optical fiber bundle corresponds to the area of the sample, the end of which is located close to the sample for detecting any light emitted therefrom. The apparatus further includes a sensor for measuring the relative position of the housing relative to the ground engaging member. This single optical output can be coupled to a fast photodetector. Related apparatus and methods are also described. The base unit also includes a transceiver and a processor configured to receive the at least one operating parameter of the vehicle from the vehicle communication module and process the at least one operating parameter to detect an event, wherein the event is used for driver compliance logging.