Well; I'm new to this PMR/Prednisone episode but have the same "weak leg" syndrome, like shaky weak, can't walk, unstable, etc. I also have pain in my prior surgical, Abbot Spinal Implant rear back area as if it is being attacked? I also gained 7 pounds, but now lost that along with my appetite. I take a Chemo orally, along with use of Tramadol for my back pain, which is timed accordingly to be spaced from the Prednisone intake, best for me at 5 A.M. but leaving me Lethargic until late afternoons and evening times. Personally, I believe this to be mostly attributed to the Prednisone, not all on the PMR? I have no advise from doctors so am controlling my Prednisone Weaning myself at the expense of learning right or wrong. I hope no one else has to do as I am. I would check interaction of all muscle relaxers or OTC meds before mixing with the Prednisone, try elevating your legs with a pillow while sleeping, also your neck and see if that helps. Celebrex never helped me, but Tizanidine does when I have to take that-hopefully never. I have found squats from a sitting position, in a chair, using your arms straight, braced on each arm of the chair and doing like a raise from sitting to sitting-push up tyoe does wonders for legs, arms and core.