Hello I'm a 400/800 runner with PR of 52 and 2:03 I'm trying to go sub 2 and at least 50 right now I'm training for cross country and have been doing 30-35 miles a week and lifting at least twice a week how much mileage do you feel is appropriate for me to be running to much mileage ends up leaving my calves and shins in pain. I've been doing like 7 mile runs and long runs of 90mins.