In Kinesiology, we consider only functional unbalances and not organical/neurological/anatomical conditions. 
A muscle that responds “Strong” to MRT and cannot be inhibited using one of the muscular inhibition techniques (see muscle correction techniques) is a Hypertonic muscle. This state is caused either by an Underfacilitated antagonist or by an Overinhibited agonist.
For more details see “The seven states of stress” by Richard Utt.