Muscle weakness refers to a reduced ability to exert force with muscles, making it difficult to perform everyday activities. It can affect one muscle group or multiple groups and may result from various causes, including injury, illness, or neurological disorders. Conditions like muscular dystrophy or multiple sclerosis can lead to significant muscle weakness. This condition can be temporary or chronic, depending on the underlying cause. Symptoms may include fatigue, difficulty lifting objects, or trouble climbing stairs. Treatment often involves physical therapy, medication, or lifestyle changes to improve strength and function. Regular exercise can also help maintain muscle health.