How can I help my dog?

We live in a 3rd floor apartment, so our dog's can't really run around inside. Even though our downstairs neighbors have told us they don't mind, dog's need to run around, and it's part of living in an apartment, I really try to keep their running around and rough play at a minimum. The apartment complex next to mine has a little fenced in dog park, so we take them there whenever we can along with regular walks as well.

Both of our dogs love to run around and play inside, but when we go to the park, one of them wants to run and play, but the other one just wants to walk around and sniff. I want him to run and play outside where he can actually run around, but he doesn't want to. Our other dog tries to play with him, be he has no interest. We have tried bringing toys and running around with them, but he still just wants to sniff around.

It's a little frustrating for me because he is so energetic and has fun running and playing inside, but he won't when we go to the park.