Yes, it means exactly that. I don’t know if you have ever done any weight lifting? Anyway, if you are lifting weights and doing multiple reps there will come a point when you can not lift the weight any more. This means that the muscle is exhausted. If after a minute of doing Kegel’s you can not do anymore, take a break of 1-2 minutes then try and do some more. Gradually you will be able to build up the amount of Kegel’s you can do. You’ll also be able to increase the length of time you can hold the Kegel for. The more you work it the stronger it’ll get.
The newbie routine recommends 2 days on 1 day off, but I think it would be better to do the Kegel’s every other day, as it is a muscle like any other and so after being worked will need 48hrs to recover. My 0.02.