1 Fit Mutt

When I see people running with their dogs, the dogs are often straining against their leads ahead of their owners. This looks very uncomfortable to me, but some of the runners I see are actually looking quite happy and not inconvenienced by the pulling at all. I've always recommended that people teach their dog to run beside them on a loose lead for safety and comfort reasons, but is this really the best way to go? If someone's happy running with...