DETROIT—Numerous sources confirmed Friday that Detroit Lions wide receiver Calvin Johnson probably works out at the gym fairly regularly, speculating, after they watched the two-time All-Pro run across the football field, that the 26-year-old must do one of those spinning classes or something. “He looks pretty fast and jumps around a lot during games, so he probably goes to the gym at least twice a week,” said Lions fan Drew Jenkins, adding that the 6-foot-5, 235-pound player likely knows how to lift weights. “His legs seem strong. He can probably ride on the exercise bikes for a really long time without getting tired. I bet he owns a bunch of different exercise videos, too. That’s the type of guy who gets a gym membership after New Year’s and actually sticks with it all year.” Eyewitnesses, who spotted Johnson leaving Ford Field in a customized Porsche Panamera after a game last season, guessed he might also have a pretty high-paying job.