Bladder control depends on muscles working together when the bladder is filling. The bladder muscle should be relaxed when it is filling. The muscles around the urethra (the tube that urine passes through), called the pelvic floor muscles, should be contracted during filling. Exercises that strengthen the pelvic floor muscles can help hold urine inside the bladder. This prevents leaks by increasing the firmness of the pelvic floor muscles. These are called pelvic floor muscle, or Kegel exercises, named after the doctor who developed them.