don't depend on a collar or a leash when you need to train.
when you get close to the dog park and your dog starts to pull
use that time for training him not to pull, to heel, etc. a dog park
is a great training tool. i used the dog park a lot when i was training
my dog. don't wait untill you're going to the dog park for your dog to
run around. go to the dog park several times during the course of a
day and train. you could let your dog enter the dog park as a reward for training.
i use to train in the dog park parking lot. as my dog learned i moved closer and
closer to the enclosure. i trained along the fence of the dog park.
as my dog was getting stronger with his commands working along the
fence of the dog i started going into the dog park for training. when we entered
the dog park i only gave him a few commands. as he learned i gave
him more commands and from a distance. his reward was always
a release and praise and then being allowed to run around.
"Life Without A Dog Is A Life Unfulfilled"