This is such a good question. And I hear this all the time from men. If you had a prostatectomy, you likely recovered a lot of strength afterwards by doing your Kegels.
If radiation therapy was then necessary down the road, this may have resulted in post-radiation fibrosis, where the tissues around your pelvic floor became shortened and less mobile. Muscles that have this fibrosis cannot lengthen as well; and with this shortening of tissues and resultant scarring comes a loss of coordination with Kegels.
Many men after radiation treatment to their pelvic floors have tight muscles; and tight musculature can drive urinary leakage. Furthermore, the more a person tries to strengthen tight muscles, the more these muscles fatigue more rapidly.
You may be doing Kegels faithfully. But if you have tight muscles, strengthening alone won't be as effective and can cause more leakage. Going for pelvic floor physical therapy can help. If that isn't an option, refraining from heavy lifting (this causes breath holding), sitting down to pee and learning to breathe deeply are great alternatives.
Finally, the pelvic floor muscles start working in the morning, when you stand up. The reason why incontinence is worse for everyone at the end of the day is because these muscles are TIRED. They have held up the organs of your pelvis, abdomen, chest and head all day! My suggestion is to recline in a chair or bed with your legs elevated at 3 or 4 pm. Stay there for 15 minutes. This will eliminate the effects of gravity and allow your pelvic floor muscles a much deserved rest.
Becca Ironside, Moderator