The causes of muscle soreness and weakness in patients may be caused by overexertion, fever, calcium deficiency, etc., as follows: 1. Overexertion: Due to the recent large amount of sports or physical labor, in the case of excessive exercise, it will cause the accumulation of lactic acid in the muscle parts, so it will manifest as muscle soreness and weakness. 2. Fever: In the case of fever, the body’s basal metabolic rate will increase in high fever The rate of glycolysis will increase, causing a large amount of lactic acid to accumulate in the joints and muscles of the body, which will lead to joint pain and muscle weakness. This situation will be significantly relieved when the body temperature drops back to normal. 3, calcium deficiency: calcium deficiency will cause an increase in neuromuscular excitability, which often leads to soreness and weakness in the calf muscles at night, and sometimes cramps in the calf.