Leg muscle lactic acid buildup can be determined by clinical symptoms and whole blood lactate measurement. Lactic acid buildup in the leg muscles is mainly due to the lactic acid produced by glucose metabolism in the body after strenuous exercise, which cannot be broken down into water and carbon dioxide and excreted from the body within a short period of time, thus leading to the accumulation of a large amount of lactic acid in the body. To determine the amount of lactic acid in the leg muscles, whole blood lactic acid can be measured by spectrophotometry. When lactic acid builds up in the leg muscles after exercise, the body experiences symptoms such as leg soreness and swelling. These symptoms can also be used to determine that there may be lactic acid buildup in the legs. Lactic acid buildup in the leg muscles needs to be determined under the guidance of a doctor, taking into account the symptoms and relevant tests.