Extensor digitorum longus muscle is located in the anterior side of the calf, is a part of the calf anterior group of muscles, to move down the behavior of the tendon stops at the back of the toes of the 2nd-5th toes, the muscle soreness and pain, there are a few common reasons as follows: First, calf strain and injury, the group of muscles is located in the anterior side of the calf, easy to cause impact injuries, long term walking and standing are also prone to lead to the strain of the muscle, thus appearing uncomfortable. Secondly, it can be seen in lumbar disc herniation, which is commonly seen in lumbar 5-sacral 1 disc herniation compressing the nerve root, thus leading to the symptoms of the toe extension muscle innervated by the nerve root. Thirdly, diseases around the knee joint of the lower leg, resulting in peroneal nerve compression, the extensor digitorum longus muscle is mainly innervated by the peroneal nerve branch of the peroneal nerve, so the disease around the knee joint can also occur peroneal nerve compression, which leads to peroneal nerve problems, and the occurrence of the extensor digitorum longus tendon pain sensation. In addition, cold and other adverse stimuli in daily life can also lead to this symptom.