when you say calf and shin, it's confusing as to what injury this is, so I'll defer to the docs, but for a specific type of calf injury where you cannot push off at all, you do walks with a tiny amount of very slow jogging interspersed every half mile or mile, gradually building up the jogging portion day by day until you can go the full distance, and wait weeks or more before doing speed again, and for shin splints, you stand on a step, facing down, with your foot half off the step and you rotate your foot up and down below the tread many times (even more effective is to do that exercise lying in bed on your stomach with your foot just over the edge of the mattress, because that allows you to push your foot forward into the resistance of the mattress edge).