When an officer uses excessive force, then that is what is commonly referred to as cop brutality.  Officers should only use the degree of force necessary to respond to the present threat or situation.  So generally, no, it's not legal for an officer to throw you to the ground if you are not resisting arrest.  However, the courts will look to more than just the act of throwing the defendant to the ground to determine whether the event actually was cop brutality.  Other factors could affect the determination including:  whether a defendant had already evaded on foot and verbal threats by a defendant to harm to officer or a third party. If you feel like you have been the victim of excessive force, then visit with your criminal defense attorney and possibly file a complaint with the agency that the officer works for.  Just remember that anything you put in the adminsitrative or civil complaint could be used against you in your criminal case.