According to the reporting surfaced in the discussion around the Flyers incident, the claim is that Mike Babcock made players spend about 50 minutes on the ice during that Detroit-era punishment story.

I couldn’t verify a direct Nasty Knuckles transcript in the available results, but the commonly repeated account tied to that incident is that the session was roughly an hour, and the “50 minutes” figure is the one most often quoted.

Context

The story is part of a broader set of criticisms about Babcock’s coaching style, especially the way former players described his tactics as humiliating or excessively hard on veterans and rookies.

Bottom line

For the specific question, the answer is about 50 minutes on the ice.