Prayer in Times of Trouble

Davening to Hashem in a time of trouble is best epitomized by Tehillim Chapter 20. Why does Dovid Hamelech refer to Hashem specifically as "the God of Yaakov" in that Perek?

Davening to Hashem in a time of trouble. Presented by Rabbi Yosef Grossman, OU Director of Kosher Education and host of "The Good Vort" on OURadio.org. Recorded live at OU World Headquarters NY, NY December 17, 2008.