It's a balance and all down to priorities, my 10 /5k time would only improve when doing 30+miles a week for months, easier to priorities of you don't have martial arts, weights it any other activities. 33min is still a good time. Shin splints really suck also! I know a few people who can't run much at all without suffering. I used to have issues and changed my run form and also wear different shoes (as I'm overpronator). Still get shin splints of I walk much in dress shoes or train barefoot on hard floor.