There are both theoretical and experimental data which strongly suggest that the intramolecular dynamics of the protein matrix play an important role in protein functions. The interrelationship between theory and experiments is rather weak mainly because of the lack of relevant experimental methods and (model-dependent) misinterpretation of experimental data. We give a short account of a few fluorescence-quenching techniques that can provide adequate information concerning protein dynamics provided that the experimental data sets are correctly processed.