Right Dr Ed I didn't mention weight pulling. But both using backpack with weight indoors on the treadmill and pulling heavy chains outdoor are useful. After a serious rehab my dog looked like Arnold! An important aspect of rehab is to develop balanced mussel mass.
For weight pulling later on outdoors I have a Pull Harness, tie down bungies with caribiner clips. Make sure you setup lengths of bungies and clips so they won't rub on dogs ankles. and a I cut 10 3' lengths of heavy chain each length weighing 5 pounds. Start with 1 length clipped on per side the increase as needed.
I would slap on the harness a few lengths of chain an go for a walk.