Yesterday I did the elliptical AND then rode my bike to and from work for a total of an hour of good cardio.
I also did lots of PT exercises and strength training exercises from my coach.
Today I was going to try 12K. I started walking and made it just a few steps when my shins started screaming. Yeah...they are still sore from the half marathon; the right more sore than the left, but still sore. I figured it was just the downhill at the start of my route, so I kept going until I got to 500m where it is flatter. Shins were still screaming. I stopped to stretch, considered what I should do, and turned back for home. I'm paranoid about shin pain since hurting my anterior tibialis a couple years ago just before the 15K in May, and I didn't want a repeat of this, so I decided to stop.
I went to the gym, did about 25 min on the stationary bike, and then 20 min on the elliptical. After that I got the kids to school and then biked to work (another 25 min of cardio). At least I got about the same amount of cardio that I would have from the 12K.
I'm hoping that my shins will permit 10K tomorrow. We'll see.