Delayed onset muscle soreness (DOMS) refers to the phenomenon of muscle soreness which often occurs after the body's unadaptable exercise, especially centrifugal exercise, or sudden increase of exercise intensity. It mainly manifests as local tenderness and muscle pain, and often accompany with muscle stiffness, acid swelling, limited joint movement, etc. In severe cases, it may occur acute soft tissue injury related symptoms such as muscle fiber rupture and muscle strength decrease . The symptoms of DOMS are also related to the inflammatory response of sarcomere rupture . At present, the physiological mechanism of DOMS is not clear. In 1902, Hough put forward the hypothesis of "mechanical injury", and thought that DOMS was related to the tear of muscle or connective tissue, as well as the obvious changes of the ultrastructure and contraction structure of skeletal muscle . This is also the first time DOMS has been proposed. The hypothesis of "ischemia spasm" thought that, the pain caused by muscle ischemia after exercise will lead to muscle fiber spasm, aggravate local ischemia and form a vicious circle . Theory of acute inflammatory response hold opinion that Ca2+ trigger a series of inflammatory reactions after mechanical injury , and the inflammatory mediators such as neutrophils, eosinophils and basophils are increased . Inflammatory reaction and production of ROS may be the core causes of DOMS, and the interruption of excitation / contraction coupling process of muscle fibers and the disorder of muscle fibers may also be the possible causes .
Clinically, the treatment of DOMS mainly include hydrotherapy, ultrasound, vibration, electrical stimulation, laser therapy, anti-inflammatory drugs, acupuncture, etc. But there are different opinions on the evaluation of curative effect [9–14]. Massage is one of the important methods in treatment of DOMS in traditional Chinese medicine. It has a good effect in reducing pain and improving muscle fatigue . Modern neurophysiology has found that pain is related to the disorder of neurotransmitters such as 5-hydroxytryptamine (5-HT), acetylcholine (Ach), dopamine (DA), β-endorphin (β-EP) and γ-aminobutyric acid (GABA). Research found that massage can reduce the release of 5-HT and DA in peripheral blood, and increase the release in central system [16–17], β-EP  and GABA  also increase. This plays an important role in the process of analgesia.
The dorsal horn of the spinal cord in the nervous system is a very important integration center in the pain afferent system, and also a key part in the mechanism of massage analgesia. In 1965, Melzack and well proposed the "gate control theory", which is the most ideal explanation for dorsal horn neurons. Type A afferent fibers excite SG cells, while type C afferent fibers inhibit. Injury cause Type C afferent tension activity, at this time, the gate is opened. Massage stimulates SG cells by stimulating Type A fibers so as to close the gate, inhibit the activity of dorsal projection neurons (T cells), reduce the transmission of harmful information to the center, and relieve the pain. This explains how massage plays an analgesic role by inhibiting pain signal transmission at the spinal cord level. In addition, massage may promote venous and lymphatic return, decompose inflammatory mediators, improve nutritional metabolism of muscle, repair muscle tissue . Although massage is widely used in treatment of muscle fatigue and injury, there is controversy on efficacy of improving local circulation and assisting muscle function recovery [21–23]. At present, most of studies are about the intervention effect of massage on DOMS, while the preventive effect of massage on DOMS is less.Therefore, we established DOMS model in rats, and carried out front and post massage intervention on rats. We measured content of serum creatine kinase (CK), concentrations of mitochondrial Ca2+, Ca2+-ATPase and the expression of IL-2, IL-6, IL-8. We also use scanning electron microscope to observe the changes of rat skeletal muscle. Through the above study to observe the prevention and effect of massage, find the best time for intervention, and provide scientific basis for the prevention and control of sports fatigue.