At one year old you definitely need to build it up slowly, Labs can get osteochondrosis in their front legs. I run with my westie. I started short runs off the lead when he was one and he turned two in October and can run 10km. The first time we ran 10km, I was worried, but we had already done 45 mins many times before, so it was only another 15 mins on top. He now does all my short runs of up to an hour with me. He has a harness that he only wears when he is running, so he knows what is expected of him. Strangely he is far more obedient when we are running. He is much better off the lead than on, he likes to run at his own pace. My dog trainer told me that if your dog lays down, rolls around in the grass or does other funny/silly things, its his way of saying he needs a break. Like someone else said, its best to run off road in places where you know your dog can get a drink. I always say my dog is a duathlete as he always swims as well when he is out on a run. Alternatively do what someone else said, use your dog walking as a warm down after a run.
