Wearing a jockstrap in a sport that does not need one can cause damage to the groin area. For example, wearing a jockstrap for sprinting is not necessary and could cause more harm than good. Instead of offering support, it will instead restrict the movement needed for the sport. Compression shorts are a far better option, as they fully fit the legs and act as another layer of clothing while still offering support.
Tinea cruris, otherwise known as crotch rot and jock itch, is a groin infection that jockstraps can cause. Warmness and dampness can contribute to crotch rot, as well as the rubbing of a jockstrap. You can avoid crotch rot by keeping the groin area clean and dry by bathing, especially after sports activities.
Wearing a jockstrap in the wrong size may cause discomfort due to decreased circulation. The straps will dig into the thighs and the cup will press harshly against the groin. A basic fix is to wear the correct size, which will allow for maximum comfort and protection. Again, compression shorts may also solve this problem, provided you buy them in the correct size as well.
Lower Sperm Count
Wearing the right size is vital to the effectiveness of a jockstrap. Another problem with an incorrectly sized jockstrap is a lowered sperm count. This only occurs with an ill-fitting jockstrap that would force the testicles against the body. Body heat is a large factor in killing a man's own sperm, and this can occur without a proper fitting.