Not sure if my experience is applicable but thought I would share. I had Cushing's Disease and had a tumor removed from my pituitary gland. It took several months for my adrenal glands to kick in and begin producing cortisol again. During that time I took hydrocortisone. My legs were very weak - I had to have assistance to step up on a curb. I went to physical therapy for over a year and built back my strength. I never attributed it to the medication though; I think I was weak even before then. And I was fortunate that my adrenal glands began working again.