A system determines pedaling effort of a bicycle and includes a first detector to generate a first sensor signal responsive to passage of a force transmission chain across a first frame-fixed point located in proximity to the force transmission trajectory of the force transmission chain, a second detector for generating a second sensor signal responsive to passage of a force transmission chain across a second frame-fixed point located in proximity to the force transmission trajectory of the force transmission chain, and a controller configured to receive the first and second sensor signals and configured to determine a first pedaling parameter proportional to tension of the force transmission chain by using the first and second sensor signal. A corresponding method for determining pedaling effort of a bicycle, and a computer program distribution medium including instructions for executing a computer process in a digital processor are also disclosed.