Is a polar bear stronger than a grizzly bear?

The largest bears on the planet are found on Kodiak Island, Alaska. They are Kodiak Brown Bears and they are hugh. I lived on Kodiak island and have seen many of them in the wild. They are magnificant to watch from a distance. Yes they are stronger than a grizzly. The grizzly is the inland brown bear, same species, different race.

In addition:

Kodiak bears are the larges sub-species of brown bear. They are about the same size as polar bears.