Meet Bertha and Olga, JC Latham's new nemeses.

Latham, the Tennessee Titans' first-round pick, took the field for the first time as a Titan on Friday for the first day of rookie minicamp and was introduced to offensive line coach Bill Callahan's "climb sleds," two specially-formulated blocking dummies that Callahan designed to best simulate the act of barreling into a defensive tackle. Before the first drill began, Callahan informed his linemen that the sleds are named Bertha and Olga.

When Latham squared up for his first try against Bertha, Bertha squared him right back down.

"On my first rep when he wanted us to move it, I shot out of my hips and got it straight up," Latham said. "If you get it straight up, you’re not going to move it as a D-lineman. It’ll be a stalemate. So you’ve really got to gradually drive as you rise with your hips. That was something I was learning as I went. It really emphasizes technique."

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So Latham reset to try again. Callahan joked about "not wanting to take all of (Latham's) money" with one drill. So Latham, who can squat 1,000 pounds, got up under the 380-pound dummy and shot it straight up again. He paused, hopped, set his feet beneath him and drove his legs as Callahan implored him to "take another bite." Five seconds of leg drive later, Latham survived the encounter.

"I don’t know if you guys know this: I think my dad invented that sled," Titans coach Brian Callahan said of his father and offensive line coach. "It’s designed in a way to more accurately mimic what it feels like to have to clamp and brace on what a normal defender would feel like. Some of the old school sleds don’t give you the same balance issue. They’re really hard to move. I can’t tell you how hard those things are to move, and to move straight. They tip, and they’re off balance. They’re meant to really stress guys’ abilities, to strengthen their core, keeping their hands tight and be able to drive the sled vertically instead of getting all off-kilter."

Latham has made no secret about his fondness for the elder Callahan. The two talked ball and watched film for two hours on Latham's pre-draft visit to Nashville. Now Callahan is peppering Latham with details at warp speed and Latham said he's doing his best to absorb the coaching.

All kinds of coaching, that is: Positive. Negative. Asking Latham to sit in his stance for two minutes straight in a meeting to demonstrate proper knee bend and weight distribution. All of it.

"He’s very, very educated with the detail of the work," Latham said. "If you had a bad rep, he’ll just tell you your rep sucked. If you did good, he’ll let you know you did good. He’ll give you areas to improve on. He’s really interesting."

Is Tennessee Titans' JC Latham playing left tackle yet?

The big question for the Titans' first-round pick is about how he'll be able to translate from playing right tackle in college to playing left tackle in the pros. The first day of rookie camp didn't involve much position-specific work for anybody. Brian Callahan said he and the staff are more focused on the fundamentals of getting players in stances and lined up in the right places than they are about more advanced work.

That said, any time Latham crouched into his stance Friday, it was a left tackle's stance.

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Nick Suss is the Titans beat writer for The Tennessean. Contact Nick at nsuss@gannett.com. Follow Nick on X, the platform formerly called Twitter, @nicksuss.

This article originally appeared on Nashville Tennessean: Titans rookie minicamp: JC Latham foiled by Bill Callahan's sleds