Compression shorts support the major muscles in your leg with bands of sturdy fabric, according to Medicine Online. This support limits extra muscle motion, or “oscillation,” during running strides to make your movements more efficient, notes research published in the May 2006 issue of "International Journal of Sports Medicine." This aids in athletic performance because it reduces the amount of energy you are expending. The 2006 finding echoes results published in the 2003 "Journal of Sports Sciences" that noted that the hip flexion angle was reduced during a 60-meter sprint among athletes wearing custom-fit compression shorts. This may suggest stride frequency was increased, notes Peak Performance. The 2003 study also reported that muscle oscillation was decreased for athletes during vertical jump landings.
In sprinting, the elasticity in compression shorts' spandex-type material appears to assist the hamstrings in controlling leg movement at the end of the swing phase, according to the 2003 study. That is because the shorts provide increased flexion and extension torque at the end range of the required motions.
Compression shorts can delay muscle soreness by compressing the muscle tissue enough so that less damage occurs, report Margaret Estivalet and Pierre Brisson in their book, “The Engineering of Sport 7.” The authors also note that muscle force capacity recovery is accelerated with compression garments. Due to their support, compression shorts reduce impact force to muscles by 27 percent as compared with U.S. football pants alone, the 2003 study reported.
The compression in such shorts also may improve blood circulation throughout your workout and reduce your use of oxygen. Studies show a lower aerobic energy cost among people wearing compression shorts than those performing without them, according to Peak Performance.
Compression from the supportive shorts increases the amount of lactate retained in muscles and thus reduces the amount that is released into the blood. Lactate impacts muscle fatigue.
Compression shorts may help cool the body by wicking sweat from the body and allowing it to disperse faster. This keeps you cooler as you exercise. Controlling the body’s thermoregulatory system can help athletic performance, as core temperature increases are associated with a decline in athletic ability.
Compression from the shorts may protect against a venous thrombosis, a condition that occurs when a blood clot forms in a vein that is deep inside a person’s body.