Shake Rattle And Roll

With my advancing years and the weight of my mighty megapixie D810 I’m finding it increasing difficult to keep the camera steady throughout a photo session. Now I do own a tripod, a Gitzo, bought aeons ago for my medium format photography. It is so massive I think it’s capable of supporting a medium sized anti-aircraft gun but I’m reluctant to start using it again because I’ve always believed that one of the major faults in my snaps is that they look far too static and a tripod is only going to compound the problem. I suppose I do have the option of switching to my smaller lighter Sony NEX-5N camera, or even cutting the length of my photoshoots and saving some money to boot. What are my other options? I’ve been looking at monopods but I’ve not seen anyone using them in a studio situation, only outdoors supporting weighty telephoto lenses. Has anyone tried using a monopod for a glamour shoot and got an opinion to share? Failing all else I might have to get into the gym and do a few weights to build the muscles back up.