There are many patients who think that their sperm count is good, how come they just can’t have children and often complain about it, but in fact there is a problem in the speed of sperm movement. Among the semen examination indicators, sperm vitality is a very important indicator. Despite a normal number of sperm, they are also unable to have children normally due to their lack of motility and slow running speed. In terms of judging the speed of sperm movement, in the past, subjective judgment was made only by the examiner under the microscope based on the results of visual observation, which was not only influenced by the technical level of the examiner but also carried considerable subjectivity; in recent years, the examination methods have been improved and the application of computer-aided sperm analysis (CASA) technology has brought the level of semen examination to a very precise and perfect level. According to WHO standards, sperm motility is classified as: ① class a: fast forward motion (speed ≥ 25 microns/sec at 37°C or ≥ 20 microns/sec at 20°C; 25 microns is approximately equivalent to the length of 5 sperm heads or half of a sperm tail); ② class b: slow or sluggish forward motion; ③ class c: non-forward motion (speed < 5 microns/sec); ④ class d: no motion. Within 60 minutes after ejaculation, less than 50% of sperm with forward motion (class a + class b) or less than 25% of sperm with fast forward motion (class a) are called weak spermatozoa. In those who have too little sex and make abstinence for too long, the percentage of forward-moving sperm will be relatively reduced due to a large number of sperm death caused by storing sperm in the reproductive tract for too long, so this cannot be considered as weak spermatozoa. Therefore, when analyzing the cause of weak spermatozoa, the effect of too long abstinence should be excluded. A correct judgment can be made by re-measuring semen after 2 to 3 days of abstinence. The common causes of weak spermatozoa are: (1) endocrine abnormalities: pituitary gland diseases can cause hypogonadism due to insufficient pituitary function, resulting in reduced libido and intercourse ability, testicular atrophy, reduced sperm production and reduced viability; prolactinoma can cause a significant increase in blood prolactin levels, resulting in reduced secretion of gonadotropin-releasing hormone, interfering with the secretion of luteinizing hormone, which in turn reduces testosterone secretion. Diabetes, adrenal and thyroid diseases can cause testicular spermatogenesis disorders resulting in reduced sperm production and vitality. (2) Immunological factors: Spermatozoa are antigenic and can induce the body to produce anti-sperm antibodies, which can cause spermatozoa to agglomerate with each other and affect the forward movement of sperm; with the participation of complement, anti-sperm antibodies can inhibit sperm movement, change the direction of sperm movement in the cervical mucus, cause sperm to tremble when passing through the cervical mucus and affect the ability of sperm to penetrate the cervical mucus, interfering with the fertilization process. (3) Genital infections: Mycoplasma solium and Chlamydia trachomatis cause epididymitis and prostatitis, resulting in reduced semen volume, reduced sperm motility and increased malformation; herpes simplex virus and human papilloma virus infection cause increased malformed sperm and reduced motility; prostate and seminal vesicle specific and non-specific infections can lead to insufficient secretion, resulting in reduced semen volume, lack of semen nutrition, acidity and alkalinity, and poor semen liquefaction. change, poor semen liquefaction, resulting in sperm aggregation, reduced vitality, shortened life span and even death. (4) Varicocele: Due to the increased pressure in the spermatic vein, blood reflux is blocked and stagnant, which affects the blood circulation in the testes, leading to carbon dioxide accumulation and oxygen deficiency in the blood, increased concentration of harmful substances, increased content of free radicals, and increased local temperature of the testes, which interferes with the metabolism of the testes, resulting in reduced sperm vitality. However, semen quality is not proportional to the severity of varicocele. Sometimes varicocele is already very serious, but semen quality is still very good and conception is still possible, while sometimes varicocele is very light, but semen quality is very poor. (5) Physical and chemical factors: toxic and harmful substances such as heavy metals and organic compounds can interfere with and inhibit the spermatogenesis process, leading to reduced vitality and impaired fertilization; radiation can lead to changes in gonadal structure and endocrine function, resulting in spermatogenic disorders and reduced sperm vitality; elevated local temperature of the testes can damage spermatogenic cells and cause a decrease in sperm vitality; some drugs can affect sperm metabolism and cause a decrease in sperm vitality. Heavy smoking or long-term alcohol consumption can cause spermatogenesis disorders, reduced sperm count and reduced motility; some nutrients and trace elements are necessary for male reproductive physiological activities, and lack of these substances in the body can lead to reduced energy required for sperm activity and reduced sperm motility, such as vitamin A, vitamin C, vitamin E and trace elements such as zinc and selenium.