That's a big mess of a situation.
Police chase. Reckless endangerment. Treating the suspect as if he is armed and dangerous (due to prevalence of guns in US). Brutal arrest. Possibility of internal injury via arrest. Police lying (apparently more common than it ought to be).
Racial motive? Who knows. American police people seem to need to be seen to be in charge to the point that anyone they arrest must be seen to be totally submissive.