Measuring muscle strength and establishing paretic symptoms are done first of all by having the patient perform actions or movements that require normal muscle strength. Measuring or grading the strength of separate muscle groups is usually done by means of the so-called Medical Research Council (MRC) scale that runs from 0 to 5, with the movement against gravity as an important criterion. This scale is not very valid in tract 4 (more strength than needed to overcome gravity, but still subnormal). Using a manual dynamometer or a fixed dynamometer it is possible to measure the strength of most clinically important muscle groups of the extremities and to compare them with values found in a normal population. For following the individual patient with a neuromuscular disorder, strength measurement with the dynamometer is more reliable than grading using the MRC scale.