Breaststroke back pain may be related to the following causes: 1. There may be a case of lumbar muscle spasm. This condition is often seen when the patient does not warm up well, and then rushes into the water, or does a wide range of activities in the water, involving the trunk. This leads to a transient spasm of the lumbar muscles, which leads to back pain. 2, there may be lumbar muscle strain or lumbar muscle sprain. The former is often seen in patients who have had long periods of sitting and standing before, which leads to lumbar muscle strain and painful episodes when going into the water. The latter is seen when the patient does excessive lumbar activity when entering the water, which leads to lumbar muscle sprain, resulting in lumbar pain. 3, there may be lumbar vertebral body slippage. If the patient has a previous slipped lumbar vertebrae during breaststroke, this swimming posture may induce an increase in nerve irritation caused by this disease, which may lead to lumbago. 4. This condition may be caused by a herniated lumbar disc. Patients suffering from this type of disease, if they do not undergo thorough treatment, they will go into the water to swim breaststroke, which may also lead to increased pressure on the nerve roots, leading to low back pain.