choc lab tugging

Question
Hi, the dog is a 5yr  old male purebred choc lab  blockhead 97lbs and in great shape akc,etc...will be nuetered soon.  I got him from a friend that needed to get rid of him. He's an awesome dog, he goes pheasant hunting with me and always gets plenty of exercise in the fenced in backyard, he goes to the lake a lot too.  I have had him for a year now.  He gets tons of attention.  the problem is when i take him to the dog park, woods, trails, etc.. he constantly tugs at the end of his leash. i have put a body harness on him so he doesn't tweak his neck, that helped a little but he is constantly sniffing and wanting to be the leader.  i have tried a short leash, i tried saying NO,calmy, yelling, etc.. i tried a long leash and every time he gets out in front tugging i turn and go a different direction he turns and runs past me right to the front again tugging away. this has worked a little because he now will look back at me to see if we are going to turn again right away, but soon returns to tugging and wanting to be the leader.   He listens to commands when at home and knows that he has to listen to me, at home in the yard he knows who the boss is. but when he's not at home its a different story.  is there any thing i can do to get him to stay by my side when he's on a walk or jog at the park, woods, etc...thank you very much

Answer
The turning around or the walk backwards variation often works well.  Since it hasn't, try a head collar.  The leading brands are Promise,  Haltie, and Gentle Leader.  They have a strap going around the dogs nose looking something like a muzzle.  They work by pulling the dogs head around.  No other way gives you such great control with so little force.  The prong collar is now a dangerous relic of value only for its macho looks.  Do not consider using one without hands on instruction from somebody with plenty of experience with them.

Neutering is not a cure all, but should help this and other behavior problems.  It also reduces the chances of cancer.