F-wave amplitudes have been used to demonstrate changes of motor neuron excitability in patients receiving pharmacological antispastic therapy as well as in those having physiotherapy. In this study it is shown that F-wave amplitudes can also be used to document changes of motor neuron excitability as an effect of the therapy with a motorized exercise-cycle, which moves the legs of paraplegic patients in a way similar to cycling. Ten F-waves were recorded immediately before and after the therapy with a motorized exercise-cycle in 70 legs of 35 patients with spastic paraparesis. Mean F-wave amplitude, mean F-wave/M-response ratio and maximum F-wave/M-response ratio were significantly lower after therapy than before.
Conclusion: The antispastic effect of the therapy with a motorized exercise-cycle may be documented by a decrease of F-wave-amplitude parameters.