The Cyclus2 is the ideal mobile ergometer and an excellent device for mobile performance diagnostics and mobile training. For that purpose the ergometer can be stowed away nicely and easily in a special, compact transport case and be transported safely e.g. in a car or aeroplane. The assembly of the Cyclus2 is very straight forward and done in a few minutes without the use of any tools. The Cyclus2 does not necessarily require an external power supply during an ergometry and can be operated independent from mains power. A practicable mains power independent operation can be provided by an optionally available rechargeable battery.