According to a 2003 Journal of Sports Sciences study, where the subjects included 10 male and 10 female track athletes, compression garments impacted movement and muscle warmth: "Hip flexion angle was reduced. Skin temperature increased more and at a faster rate during a warm-up. Muscle oscillation was decreased during vertical jump landing. Countermovement vertical jump height increased."So, what does that mean? Well, basically, compression shorts likely increase "extension torque" and may help hamstrings control the leg during sprints: "The compressive garment significantly reduced impact force by 27% compared with American football pants alone. Through various mechanisms, these findings may translate into an effect on athletic performance and a reduction in injuries." Sounds good to me!