By testing the strength of the voluntary muscles (which means the muscles we can move at will, e.g. in our arms and legs), you can find out if the person's nerve function is normal, or has been weakened or paralysed by leprosy. The findings are recorded as follows:

• Paralysed (P): the muscle has lost all strength and cannot produce any movement;
• Weak (W): there is some movement, but muscle strength is reduced;
• Strong (S): the muscle strength is normal.