The researchers studied how selecting sperm before freezing affects its movement in bulls. They used a method called single layer centrifugation in Percoll® to separate sperm. After thawing, they analyzed the sperm's movement using a computer program. They found that selecting sperm with this method led to differences in how the sperm moved, such as how fast they moved and how straight their path was. However, there was no difference in the overall movement of the sperm between the groups.