A Normotonic muscle is a muscle that responds in a balanced way to Muscle Response Testing (MRT).  It is nor an Hypotonic Muscle nor an Hypertonic Muscle, it has a normal Tone.
The evaluation of tone performed with Muscle Response Test is functional and therefore every response (hypo, hyper or normo-tonic) fits within the “normal” tone of muscles. The anatomical-neurological altered tone is a pathological condition and a frankly pathologic muscle cannot be evaluated with Muscle Response Testing (MRT).