* Perceived weakness (or non-neuromuscular) describes a condition where a person feels more effort than normal is required to exert a given amount of force but actual muscle strength is normal, for example.

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. This is also true for some cases of Myalgic encephalomyelitis/chronic fatigue syndrome,