Only sperm with normal forward motion can ensure that the sperm reaches the abdomen of the fallopian tube and unites with the egg to form a fertilized egg. If some factor affects the motility of the sperm, especially the forward motion, this will prevent the sperm from swimming to the egg at the optimal time and fertilization will not occur. In addition, if the sperm spend too much time in the vagina, the acidic environment will shorten the survival time of the sperm. According to domestic literature, male infertility due to low sperm motility accounts for about 30% of cases. I. Etiology 1. Infection Acute and chronic inflammation of the reproductive tract or reproductive glands such as the epididymis, vas deferens, seminal vesicles and prostate can reduce the motility of sperm. The effect of infection on sperm motility can be multifaceted. The direct effect of microorganisms on sperm, such as mycoplasma, can attach to the head, mid-section and tail of sperm, causing increased hydrodynamic resistance and slowing down the movement of sperm when they make forward motion, affecting sperm viability and the ability to penetrate egg cells. In addition, mycoplasma can cause partial sperm membrane defects or even membrane structure destruction, affecting the fertilization ability of sperm. E. coli can reduce sperm viability by binding to sperm through its own receptors; the indirect effect of microorganisms on sperm can be through the production or release of toxic substances, and mycoplasma produces NH3 during growth to have a direct toxic effect on sperm. Escherichia coli can produce sperm braking factor. Decreased sperm viability due to infection can also be achieved by changing the pH of seminal plasma, which decreases significantly when the pH is below 7 or above 9. In patients with acute adnexal inflammation or epididymitis, the pH is more alkaline, while chronic adnexal inflammation can cause the pH to fall below 7. In addition, inflammation-induced leukocytosis in semen can lead to a decrease in sperm motility through direct and indirect causes. The lack of sperm motility caused by prostatitis may be the result of a combination of factors, which may be related to zinc disorders in addition to microorganisms, leukocytes and pH. 2, abnormal semen liquefaction Semen non-liquefaction or high viscosity is one of the causes of male infertility, a very important factor which may cause infertility by affecting the motility of sperm. In seminal plasma with non-liquefied semen, elongated fibrin may be seen and intermeshed to reduce the space for sperm movement, and sperm are held back, while coarse fibers are seen connected by many fine fibers in a network, which may be responsible for mechanically limiting forward movement of sperm. The authors of this paper have used urokinase-type fibrinogen activator (uPA) alone on specimens of non-liquefied semen in vitro and found that when the semen changed from non-liquefied to liquefied state, sperm viability and forward motility increased significantly, and the same effect was obtained with chymotrypsin. 3. Immune factors Anti-sperm antibodies (AsAb) can affect sperm fertilization function in several different ways. The effect on sperm motility may be due to the binding of AsA b to the tail of the sperm, which impedes sperm motility and reduces motility and penetration ability, as has been demonstrated by the markedly reduced ability to penetrate cervical mucus when anti-sperm antibodies are present against the tail of the sperm. Some scholars have used AsAb positive serum and human sperm contact, observed a so-called sperm “shaking phenomenon” (shaking phenomenon) is mainly the head and the entire tail of sperm combined with anti-sperm antibodies, sperm forward movement is inhibited, but no significant change in survival rate. 4, endocrine factors endocrine hormones, in addition to their role in spermatogenesis and maturation, also affect sperm motility. gonzales et al. found a linear relationship between prolactin in seminal plasma and sperm activity, which improves sperm oxygen uptake or affects sperm motility through the cAMP system. when serum E2 levels are elevated, sperm motility is reduced. Excessive testosterone in seminal plasma may inhibit sperm motility. 5, syndrome In the early 1930s, Kahl was the first to identify a condition that was later confirmed by other scholars to be a congenital lack of ciliary structures, manifested by the inability of the cilia of various ciliated cells in the body to move, mainly the absence of the ciliary dynein alms of peripheral microtubules. Patients with this syndrome may have chronic respiratory infections traced from their medical history, in addition to the inability of sperm to move. 6. Chromosomal abnormalities Autosomal and sex chromosome aberrations affect sperm viability and forward motility, in addition to sperm count. The ultrastructural apparatus known to be associated with sperm motility can have abnormal sperm tail structure due to genetic factors, for example, lack of inner or outer branched arms or absence of both arms. It can also be the lack of central junctions and central complex structures, because the interaction between the central microtubules and the radial spokes can mediate the gliding of the outer microtubules, and when this structure is abnormal, the spermatozoa can have impaired motility. Varicocele can lead to male infertility in several ways, not only by affecting the occurrence of spermatozoa, but also by causing a decrease in sperm motility. The mechanism may be due to blood stagnation in the varicose veins, impaired microcirculation, lack of nutrient supply and reduced partial pressure of oxygen, insufficient energy production and endocrine dysfunction. In addition, varicocele may also cause autoimmunity such as the production of anti-sperm antibodies and mycoplasma infection to indirectly cause the decrease of sperm vitality. 8, other factors Trace elements in seminal plasma zinc, copper, magnesium and semen quality, seminal plasma zinc content is more than 100 times the plasma content, low sperm vitality patients in the seminal plasma of zinc, iron, magnesium content is significantly lower than the vitality of normal healthy men. Zinc delays lipid oxidation of cell membranes and maintains the stability and permeability of cell structure, thus ensuring good sperm motility. High levels of the trace element cadmium (Cd) can lead to reduced sperm motility, cadmium can directly inhibit the oxidative enzymes of sperm and directly inhibit the motility organs of sperm, and the cadmium content in the semen of infertile men is significantly higher than that of fertile men. The lack of enzymes or reduced enzyme activity related to sperm motility, vitamin deficiency, engagement in high temperature, radiation occupations and exposure to chemical toxins can all cause a decrease in sperm motility. Smoking, alcohol consumption and drug factors Nicotine in tobacco affects sperm vitality through direct and indirect damage to sperm, long-term alcoholics can directly and indirectly affect sperm motility, and there are more drugs that affect sperm vitality. There are also some low sperm vitality people who can’t find the cause, called idiopathic weak sperm. The reason is that the sperm of the weak sperm has some quality problems, and even if such sperm can combine with the egg, it is not sure whether the result is ideal. 2. There is a certain chance of conception in weak spermatozoa, and even in mild weak spermatozoa the sperm motility is lower than normal, so that the quality of sperm is not guaranteed, and conception in this case still has certain disadvantages from the eugenic point of view. Normally, only forward-moving sperm can ensure that the sperm reaches the abdomen of the fallopian tube and unites with the egg to form a fertilized egg. Many pregnant women have premature births or miscarriages during pregnancy, which may also be caused by insufficient sperm quality, so weak sperm should be given sufficient attention. Prevention 1, try not to use or less use of various chemicals, from the dry cleaners to take back the clothes best put a few days before wearing, because dry cleaning agents can affect male sexual function; daily before 11 o’clock to bed, every day sweat, try to eat unprocessed pure natural food. 2.Prevent various infectious diseases that endanger male fertility, such as mumps and sexually transmitted diseases. 3, found that the testicles have different changes from the usual, such as enlargement, hardening, bumpy, pain, etc., must be timely diagnosis and treatment. 4.Avoid excessive noise. According to the data, it is proved that men live in the environment of 70-80 decibels of noise for a long time, sexual function tends to be weakened, living in the high noise environment of 90 decibels or more sexual function disorders. 5, avoid long masturbation. It will trigger slow congestion of the prostate gland, leading to sterile prostatitis, affecting semen nutrients, quantity, viscosity, acidity and induce infertility. 6, do not eat too greasy food, quit smoking and alcohol. The germ cells in the testicles are affected by the harmful components in tobacco, making the sperm quantity and quality poor.