SANFORD, Fla. -

George Zimmerman trial defense attorneys called his gym trainer to the witness stand Monday.

Adam Pollock, 43, is the owner of a gym in Seminole County.  Zimmerman joined Pollock's Kokopelli'sgym in 2010 and lost some 50 to 80 pounds, Pollock said. He also did some beginner boxing training.

"He was an overweight, large man when he came to us. [He was] a very pleasant, very nice man, but physically soft [and] predominantly fat," Pollock said. "[He did] not [have] a lot of muscle; not a lot of strength."

In a bizarre scene, defense attorney Mark O'Mara asked Pollock to demonstrate the mixed-martial arts fighting method known as "Ground and Pound" in the courtroom floor. 

Zimmerman claims Trayvon slammed his head into the sidewalk while he was on top of him. Earlier in the trial, witness John Good described the position as a "Ground and Pound" maneuver.

In an unrelated case, Pollock was charged with a felony battery by strangulation on a woman who scammed him earlier this year.