A dog and a harness.
Our nine month old puppy loves to run and can now outrun us all. We always have her on a leash outside the house or back yard. She is also (head)strong and often pulls on her leash in her need for speed. We have been using a flexible collar, but she would rather lose her breath than slow down sometimes. In my compassion for her condition, I bought her a classy new collar and a new harness so that she could run and frolic without strain on her throat. We used a harness with her when she was a small puppy and it worked well.
We put the harness on yesterday morning. You would have thought we crippled her. The tail drooped and with head hung low she slowly limped back to the kitchen. This from a dog that has only ever strutted.
She didn't bark about it, or even whine. She went to bed. And stayed there.

Her toys were worthless. She did seem to keep her favorite toy near, but feigned disinterest whenever she thought we were noticing. The cats were irrelevant and didn't deserve a chase. We tried to take her for a walk. Forget about it. All four legs and her bottom braced against any forward motion. She reluctantly did her "business" if we carried her out to the grass and insisted.
Occasionally, she strayed from her bed all the way to the kitchen floor a foot away.

We teased, we laughed, we hand fed her hot dogs. The longer she pouted, the more ridiculous it was. We left the harness on, waiting for her to adjust. After all, she adjusted to the "cone of shame" that she had to wear for a week after her surgery. It just took a day, and then she was fine.
I've had similar experiences with our kids, particularly with seat belts, and I never lost those fights, always able to outlast the most stubborn rebel.
This afternoon, after thirty-six hours, we surrendered. I guess the harness worked. As long as she was wearing it she certainly didn't strain her throat. But the means couldn't justify the end, so we took the harness off and put the old collar back on.
Immediately she was upright and ready to go.

See the tail, up and curly? It's rather humbling to be bossed around by a small dog, but it was sure fun to watch her strut, leap onto the bed, wrestle with the cats and enthusiastically request a walk.
This is our shiba inu - three pounds of dog and thirteen pounds of attitude.