Pay attention to the cop starting at about 22 seconds into the clip.
The NY Times describes the police officer's account of the assault:
Officer Pogan arrested Mr. Long [the cyclist] on charges of attempted assault, disorderly conduct and resisting arrest, the court papers say. Mr. Long, who other cyclists said works in the Greenmarket in Union Square, was released without bail on Saturday.
In papers filed in Manhattan Criminal Court, Officer Pogan said Mr. Long was weaving in traffic, “forcing multiple vehicles to stop abruptly or change their direction” to avoid a collision. Officer Pogan also said he suffered cuts on his forearms as he fell to the ground.
Officer Pogan said Mr. Long had flailed his arms, kicked his legs and refused to put his hands behind his back. He also said Mr. Long had “twisted away” from him, “thereby making handcuffing difficult.”
He said Mr. Long told him: “You are pawns in the game. I’m going to have your job.”
Once again, good thing there is video.