A Toronto police officer accused of using excessive force during the arrest of a man at a G20 protest three years ago says he fully complied with the training he had received.

Const. Babak Andalib-Goortani has pleaded not guilty to assault causing bodily harm during the arrest of Toronto man Adam Nobody.

The 33-year-old officer broke down in tears on the witness stand Monday as he recalled the events during the protests leading up to Nobody's arrest.

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Const. Babak Andalib-Goortani has pleaded not guilty to charges of assault causing bodily harm. (SIU)

He has told a court he struck Nobody with a baton because he was strongly resisting arrest as other officers were trying to handcuff him.

Nobody, a 30-year-old stage hand, has testified he was tackled at a protest at the Ontario legislature on June 26, 2010, and was hit several times as several officers piled on top of him.

Both sides agree that Nobody's arrest was lawful, but the central question is whether the force Andalib-Goortani used was lawful.