Is it the type of place that you can let him off his leash? Because dogs run at a much different pace than people do they have a hard time running on leash. Let off the leash they are able to do their smelling/peeing, and then they will run at a normal dog pace to catch up.
My mum said she could get our dog to do 8km on leash and then he became resistance training for her. But off leash in the woods she could do 14km or more and he would be good for it.
If off leash running isn't an option I suggest first of all a short leash. Think of the distance between his collar and your hand, and add just a bit of slack. Check out Halti Headcollars, they are a great help in walking/running with a dog. We had one for our dog and he would walk very happily with it (he even liked wearing it) but without it he was much more difficult to control.
other things my mum would do:
-when she went from walking to running she would say "We're going to run now." The verbal cue is a reminder that the dog should be following your lead.
-only allowed him pee stops at certain places. If you run the same routes often this is easy because a particular tree, sign post, can become one of your dogs stops. Allow ten seconds or so, and then add another verbal cue, such as "Ok, let's go."
-if the dog starts to slow down, is getting tired try walking for a bit to let him get back into it. We do 10 and 1's, dogs should be able to as well. My mum would tell our dog "You're poking" (as in poking along) if he wasn't running fast enough.
-if you're going to be out for a long time let him drink along the way. Because dogs can't sweat drinking is one of the few ways they can cool down.
Remember that your dog isn't wearing shoes, so after runs check out his paws. If they are sore, or cut he won't enjoy running at all. Particularly watch out for broken glass while running. He'll always prefer to run in the grass because of the ease on the feet.
And one final thing, it sounds like you don't have another person running with you, but if you do having the dog run between two people gives them a place to stick to and keeps their attention on running. Its harder for him to smell things, if he has to cross someones path.