The experiments involving the interaction of radio-frequency heating with fast particles injected by neutral beams on TEXTOR are reviewed. The focus point of the present study is the comparison between experiments and theory. Theory involves the modelling of RF diffusion in velocity space, absorption of radio-frequency waves by non-maxwellian populations, computation of drift trajectories to take trapping and first-orbit losses into account. A more specific theoretical development used in this context is the reconstruction of charge exchange spectroscopy spectra. Three types of experiments are examined. The synergetic increase of beam current drive by radio-frequency power, the large neutron production in third harmonic heating of D beam ions and the control of central fast helium concentration by radio-frequency induced diffusion.