Pelvic floor exercise, also known as Kegel exercise, consists of repeatedly contracting and relaxing the muscles that form part of the pelvic floor, now sometimes colloquially referred to as the "Kegel muscles". The exercise needs to be performed multiple times each day, for several minutes at a time, for one to three months, to begin to have an effect. Exercises are usually done to reduce urinary stress incontinence (especially after childbirth) and reduce premature ejaculatory occurrences in men, as well as to increase the size and intensity of erections.