Muscle fatigue is the decline in ability of a muscle to create force. It is a normal result of vigorous exercise but abnormal fatigue may be caused by barriers or interferences at many of the differing stages of muscle contraction. An important factor in muscle fatigue is the reduction in the release of Ca²⁺ (calcium) ions from the sarcoplasmic reticulum, along with falling ATP levels.

Weakness of one muscle may be due to problems with the nerve supply (e.g. neuropathy), neuromuscular disease (problems with the transmission of nervous impulses to the muscle, e.g. in myasthenia gravis) or problems with muscle itself. In the latter category belong various myopathies (muscle disorders) such as polymyositis.

See also

• Malaise
• Asthenia
• Paresis
• Debility
• Muscle weakness
• Fatigue (physical)

Neurology | Muscular system