This last Sunday I decided to step up and see where I was at in my training and opted to do a 30 mile bike loop and then run for as long as I could. I averaged 16 mph on a hilly loop without pushing it too much on the bike because I was trying to save some energy for the run. I was pretty satisfied with that effort and took off running about 5 minutes after the bike ride.
As the run started out, my legs felt really wierd as if I was floating. It wasn't necessarily a sense of fatigue but just different. I got about 1 mile into my run and had to stop because the front outside part on the bottom of my left leg was starting to throb. Not like a shin splint, but like it was going to explode if I kept going. This is a common sensation that you get from riding motorcycles, but it occurs in your forearms. Anyways, I switched to a run/walk after that to avoid injury. Once I got home, I put some ice on it and all was back to normal pretty fast.
I am guessing it has something to do with dehydration due to all the water I burned up during the bike, If anyone can offer a remedy to this sensation, I woud wlecome it with open arms.