I know nothing about radiolabeled glucose incorporation, though I did read an interesting approach using ultrasound to assess the level of glycogen in skeletal muscles a few years back. I don't remember the author off the top of my head but I suspect it would be easy to find. The authors validated their algorithms using muscle biopses.

Dan Robbins Thank you for your reply. Yes, I am aware of that paper that you mentioned. But I am really looking for more of a "real-time" method of glycogen synthesis.