What is the test for determining whether a police officer used excessive force under the Fourth Amendment?

Ultimately, "[d]etermining whether a police officer's use of force was reasonable or excessive therefore requires careful attention to the facts and circumstances of each particular case and a careful balancing of an individual's liberty with the government's interest in the application of force." Santos v. Gates, 287 F.3d 846, 853 (9th Cir. 2002) (internal quotation marks and citation omitted). Whether an officer used excessive force under the Fourth Amendment is a question for the jury, which "almost always turn[s] on a jury's credibility determinations." See id. "Because [the excessive force balancing test] requires a jury to sift through disputed factual contentions, and to draw inferences therefrom, we have held on many occasions that summary judgment . . . in excessive force cases should be granted sparingly." Id.