There are quite a few muscles involved in continence.
All are deep muscles that can be difficult to externally feel.
Continence nurses find out how well they work by getting you to flex them while feeling the strength of the clench around the finger up the anus.
There are a number of exercises that can strengthen those muscles. The opposite exercises can weaken those muscles.
The outer sphincter controls a lot of the contractions of the bladder. If it doesn't clench, the bladder contractions will become uncontrollable and the flow will be unstoppable. OAB will be the result.
The pelvic floor supports alot of those muscles. A weak pelvic floor will make incontinence much more likely. Flex that muscle outward, kinda like pushing your crotch towards you knees, hold for 5 seconds and release, 5 times three times a day.
The transverse pelvic muscle is also involved. It runs between the hip bones across the front, but it's deep under the other pelvic muscles.
Flex it out, like you are trying to spred the hip bones apart.
The bowel is also affected by the same group of muscles.
Take your pick, either clench the butt cheeks in to strengthen, or flex the butt cheeks out to weaken.
Same procedure, 5 second hold three times a day.