There are many causes of muscle weakness, the common one being electrolyte disorders, the most common causes of electrolyte disorders include low potassium and low calcium. The most common causes of electrolyte disorders include low potassium and low calcium. Low potassium causes muscle weakness, called periodic paralysis or periodic paralysis, which is caused by insufficient potassium intake or excessive potassium loss, resulting in weakness of the limbs, easy falls and difficulty moving. Low calcium can also lead to muscle weakness, as calcium deficiency, excessive sweating or taking certain special medications can cause calcium loss and insufficient calcium ion concentration in the elderly, so it can lead to limb twitching, spasms, restricted movement, and weakness of movement, so muscle weakness symptoms can also occur, and muscle weakness caused by low blood calcium can be treated by calcium supplementation.