Measuring and teaching apparatus and instruments; measuring and teaching apparatus and instruments for use with bicycles, stationary cycles and exercise and training equipment; computer software; computer software for processing and storing data generated by bicycles, stationary cycles, and exercise and training equipment; data media; data media for storing data generated by bicycles, stationary cycles, and exercise and training equipment; data processing apparatus; data processing apparatus for processing data generated by bicycles, stationary cycles, and exercise and training equipment; power, torque and work measuring devices and instruments for use with bicycles, stationary cycles and exercise and training equipment; cranks for power, torque and work measurement for use with bicycles, stationary cycles and exercise and training equipment