Sperm motility refers to the ability of sperm to move and swim forward in a progressive and coordinated manner. This swimming motion is an important factor in male fertility because it is necessary for the sperm to be able to swim through the female reproductive tract to reach and fertilize the egg. The quality and quantity of sperm motility can be assessed through semen analysis, which measures the percentage of sperm that are motile and the quality of their movement. Low sperm motility is a common cause of male infertility, as it can reduce the chances of fertilization and successful pregnancy.