When you hit the trail for a long, rejuvenating run, sometimes six legs are better than two. Your dog is a great companion and an inspired running partner. He's always available and almost certainly won't mind an impromptu workout. Actually, he'll probably be overjoyed when you drag his leash out of the closet. Whether he's taking point, bringing up the rear or matching your pace, Max (or Sparky) won't embark on a longwinded story that will require your attention, worry that his thighs look flabby or ask to stop for ice cream on the way home. Better yet, taking him along is a healthy move for both of you if you keep a few important things in mind.