Probably not. In a recent opinion by the California Court of Appeal, Third Appellate District, the Court held that ordinary people -- jurors -- are capable of determining what constitutes "unreasonable force under the circumstances" in many excessive force actions without special testimony by law enforcement use of force experts.
Unlike a medical malpractice case, where the standard of care is "peculiarly within the knowledge of experts," in many police excessive force cases what amounts to reasonable or unreasonable force is not "so far removed from the comprehension of a lay jury" as to necessitate expert opinion testimony on the issue.
The Court cited cases from other jurisdictions and found a Wisconsin case persuasive: "'Similarly, a jury does not need the opinion of an expert to determine whether a police officer acted reasonably in picking up a handcuffed individual by the belt and dropping him to the ground and then standing upon him.'"
The plaintiff in the California case, Allgoewer v. City of Tracy, sued for excessive force in California after police officers manhandled and tased him in connection with an arrest following a child custody dispute. He claimed he suffered injuries including a broken wrist and torn shoulder muscle.
The Court did indicate that there may be certain excessive force cases that would benefit from expert testimony but declined to find that the instant case fell into that category.