Start with your dog by your side; hold on to his collar if necessary. Rev the dog up with excited talk like “Are you ready? Do you wanna run?” and then say “Ready, set, GO!" and start running, encouraging your dog to run alongside you.
After running about 5-10 steps (start out with short distances at first so your dog doesn’t get too aroused), stop and ask him to “down.” Reward with a treat.
Immediately repeat the sequence. Keep the game fast moving to keep your dog’s interest. Once your dog “gets the game,” start varying the number of steps you take. Eventually, you will be able to stop treating as the reward will be getting permission to run again. If the “down” cue isn’t your dog’s strong suit, ask him to “sit” instead.