SPARTANBURG — When Rex Ryan blows up at his team – as the New York Jets’ coach did Tuesday – ESPN breaks from its Tim Tebow coverage to put the tirade on “SportsCenter.”

When the normally soft-spoken and mild-mannered Ron Rivera goes off, nobody notices.

Except the guys who play for him.

An hour into the Panthers’ practice Wednesday, Rivera stopped the drills, gathered his players around him and lit into them for what he viewed as a lackluster tempo and questionable effort. After an energetic practice Tuesday in full pads, Rivera thought some players were going through the motions Wednesday in the shorts-and-shoulder pads session.

“I wanted to make sure people understand the way you’ve got to practice. We’re starting to back off now looking to game time. ... I wanted to make the point that a lot of opportunities are being passed up by not practicing hard,” Rivera said.

“Just because we back down doesn’t mean we don’t practice hard. We don’t want the big collisions because we’re not in full pads. But to do what we did for two periods and basically waste that time, that was disappointing.”

Growing up in a military family, Rivera was taught to make every minute count. Saturday mornings were about early wake-ups and yard work, not cartoons and Cocoa Puffs.

So those 10 minutes Wednesday were 10 minutes Rivera wasn’t getting back. But the pace of the final 75 minutes picked up following Rivera’s rant.

“Practice wasn’t overly intense. I think we’ve had a good camp so far and each practice kind of built on what we did the one before, and this one started out a little slow,” veteran offensive lineman Jordan Gross said.

“The thing I’ve always respected about coach Rivera in the 12 months I’ve known him is he’s a great guy to be around and a real friendly players’ coach. But he’ll let us know when we’re not doing what he’s expecting.”

Rivera said he’s never been a yeller in nine seasons as a linebacker with the Bears or 14 years as an assistant coach. But he knows how to pick his spots.

“When I do have to say something, I try to choose and pick my moments,” Rivera said. “I trust my coaches to do their jobs and coach. That’s why they’re hired. They do a good job. The points I try to make, I have to make sure they really stand out and they’re understood. And when we’re not getting the job done, it falls back on me.”

Rivera said his message Wednesday was directed at everyone. But he wanted the young guys to know the Panthers used 17 extra players because of injuries in 2011, and many were signed off the practice squad.

In other words, August matters – for starters and fourth-team, undrafted rookies.

Rivera had a similar moment at training camp last year when he wasn’t pleased with the intensity. But usually Rivera is seen and not heard.

“When he says things, people listen. And when he says things, he means it,” offensive lineman Jeff Byers said.

The Panthers’ practice facility in Charlotte sits next to an active rail line. Trains go by frequently enough that Byers said players become immune to the rumble and conductor’s whistle.

That’s not the case when Rivera raises his voice.

“He’s not one those guys that just yells to yell. So when he does get worked up, you know he’s got reason,” Byers added.

Gross said Rivera, as an ex-player, knows how to relate to players and “doesn’t think he needs to dog-cuss us or yell at us all the time to get the job done.”