Practice was over. At least technically it was. But the teaching continued.

Iman Shumpert, Carmelo Anthony, Amar’e Stoudemire and coaches Mike Woodson and Herb Williams remained on the court at the Knicks practice facility yesterday going through an extra session of the high pick-and-roll defense.

It’s amazing how something that sounds so simplistic can be so complicated. The Knicks had used the final portion of their formal practice to rehearse the essential principles of attacking, reading and reacting. But mastering the techniques has been a struggle.

Opposing point guards from Jrue Holiday in Philadelphia to John Wall in Washington to the Clippers’ Chris Paul have been burning the Knicks lately using the pick-and-roll. Hence, the extra session yesterday in preparation for tonight’s game against the Raptors at the Garden.

“It’s not that hard,” Shumpert said of defending the pick-and-roll. “I think we make it harder than it really is. We’re just overthinking it too much. We just have to get back to being aggressive and talking aggressive. If we do that, we’ll be fine.”

Shumpert might be right. The way the Knicks questioned each other yesterday, however, it seemed they weren’t close to being on the same page. It looked like training camp all over again. The high pick-and-roll is not easy to defend, which is why the Knicks need to keep Shumpert and avoid any temptation of trading him for more offense.

With so few pieces on the Knicks roster worth exchanging, Shumpert’s name is surfacing in trade rumors. Let’s hope they’re just rumors.

It’s way too early to give up on Shumpert for several reasons. The second-year player is the Knicks’ best perimeter defender, which isn’t saying much playing next to Raymond Felton and Jason Kidd — not exactly Darrelle Revis in sneakers. Trading Shumpert would only weaken an already challenged defense.