With respect to Mayo Rochester...pain and EMG usually go to Mayo grads but not always.
One slot sports medicine fellowship--PMR based
One slot musculoskeletal medicine fellowship--PMR based
3-4 pain medicine slots--anesthesia based with usually 1-2 PMR grads per year but varies considerably
3-4 EMG/Neuromuscular medicine fellowships slots--Neurology based with usually 1-2 PMR grads per year