(or "lack of strength") is the inability to exert force with ones
Muscle s to the degree that would be expected given the individual's general
Physical Fitness . A test of strength is often used during a
Diagnosis of a muscular disorder before the
Etiology can be identified.
The term subsumes two other more specific terms, ''true weakness'' and ''perceived weakness''.
- (or "objective weakness") describes a condition where the instantaneous force exerted by the muscles is less than would be expected. For instance, if a patient suffers from Amyotrophic Lateral Sclerosis (ALS), Motor Neuron s are damaged and can no longer stimulate the muscles to exert normal force.
- (or "subjective weakness") describes a condition where it seems to the patient that more effort than normal is required to exert a given amount of force. For instance, a person with Chronic Fatigue Syndrome may struggle to climb a set of stairs when feeling especially fatigued, but if their muscle strength is objectively measured (eg, the maximum weight they can press with their legs) it is essentially normal.
In some conditions such as
Myasthenia Gravis muscle strength is normal when resting, but ''true weakness'' occurs after the muscle has been subjected to exercise.
