When I finally was feeling ready to start jogging (Chibi was a little over a year old), she would always start sprinting at full speed (which was way too fast for me). She would dart ahead and get yanked back when she hit the end of the slack in the leash. My jogging pace was right in between her trotting and walking, but not quite running, etc.
Eventually, I gave up on the jogging. Then came Sumo dog. So we were walking 2 dogs now. Sumo still pulls at the leash until he chokes himself. We've tried corrective leash action, harness, harness that pinches the legs together, a backpack, and the face harness, but he still pulls sometimes.
I decided to start running again, which made Sumo happy. He doesn't pull anymore (his pace perfectly matches my stride) and runs right beside me. Chibi now lags behind and eventually slows down until I stop running (at which time she "sits" until I stop jogging). She's perfectly content now to walk and ONLY walk. I imagine, it looks a bit odd with white dog pulling in front, red dog lagging behind, with me in the middle.
The solution is to walk both dogs when I'm the only one home, OR when mom is available, she walks Chibi and I go for a run with Sumo. The first time was interesting, the first 10 minutes or so, Sumo would stop every 20 yards or so and look back to try and find Chibi. Once he even stopped and wouldn't keep going. He laid down and just faced home.
I'm not sure if Chibi is getting older, prefers a slower pace, or is just letting me know that she could run (because she used to) if she wanted to, but because I used to not let her, she's not letting ME run now. (I'm all but certain that's it :-p)