Stepping up 10% every couple of weeks works pretty well- adjust to how you feel.

If you can ride 60 miles comfortably, then a supported century is perfectly do-able.

If 'strains' are sore muscles or sore butt- NBD. If IT band symptoms, back off a bit & work up slower.

If tendon/ joint issues- don't push through, work on fit, flexibility, etc.

(my abbreviated .02)