I am sure people will disagree with this advice, but it worked for me and I was never on light duty (which you do not want to be on, for many reasons). I started getting shin splints about a month before OCS. I quit running and used the eliptical machine and exercise bike everyday. One week into OCS the shin splints were back and they were painful. Every morning i would go see doc and get motrin. I would take it twenty to thirty minutes prior to PT. It works awesome. I was always able to keep up on all runs and in relatively little pain. Around noon chow, when the motrin wore off, is when the pain would begin. I just sucked it up when we weren't PTing and made sure i took it before PT. Around the fifth or sixth week the pain started to go away and by week eight i was no longer on the motrin. The corpsman and docs made me nervous about shin splints causing stress fractures which will cause your leg to snap in half when jumping off an obstacle. I was concerned, but not enough to get on light duty. You will be fine, just suck up the pain and take the motrin. Our plt sgt let us by our own motrin on liberty. It got me through ocs. I am finishing up TBS and have not have shin pains since OCS.