I've got a better idea. Police shouldn't beat people because they choose to run. We all make mistakes but that doesn't give police the right to beat you.
I'm definitely in the 'it depends' category. The dude that got shot in the back the other day didn't deserve it at all.
On the other hand, the guy that led Texas DPS on a high speed chase all over Central Texas back when I was in college, endangering hundreds of lives over a 60 minute period, ending with him ramming a cop car and injuring an officer, deserved to get his ass beaten severely by the cops who finally captured him, IMO, which he did.
So, every situation is a little different.
On a more serious note, there are definitely situations where physically striking someone is required to subdue them. One needs to review the entirety of the situation before drawing any conclusions. Unfortunately, between the media, the activists and the ambulance chasing lawyers, there's usually about 3 hours between the incident and the trial and conviction by public opinion these days.
