I'm sure that there are circumstances where the police, door staff (bouncers) or similar do use too much force. Whilst working in a solicitors I visited a young (white!) female who'd been arrested for something she certainly wouldn't do whilst sober. And, even though she couldn't remember it, it was accepted that she'd resisted arrest. That said, when we went in the afternoon are her wrists were still red from where the handcuffs had been put on - which suggests they were probably put on too tight (or at least not loosened after they were put on in the heat of the moment). But, it's like any occupation - there's always a very small minority who will go too far or abuse their power, and there's nothing that can be good to stop it. We can't comment greatly on this case because we don't know where the punches were delivered (although it's a good bet it was the arm), how the arrested was reacting, if the officers were managing to hold her down (I think at the time of the punches there were 3 officers? That's not enough to claim a limb each as previous commenters have mentions), and thus if in all the circumstances such use of force was reasonable. On the basis there's been no complaints before this time despite all the bouncers and other officers around, it almost certainly was. What is concerning, as previously said, is why this appears to have been made into a racial issue. Anyone who's watched any police "fly-on-the-wall" documentary will have seen the police needing to use a lot of force to restrain anyway - be they black, white, or polka-dot orange!