CHICAGO -- Von Joshua's phone has been ringing a lot lately. Ryan Theriot is keeping in touch with the Triple-A Iowa coach, and the Cubs shortstop gives Joshua a lot of credit for his recent power surge.

After going 620 at-bats without a home run, Theriot has hit three in his last four games to match his career high for a single season. He was not in the Cubs' lineup Tuesday, the first game he's missed this season. The 5-foot-11 shortstop spent most of the offseason in the weight room and does like to flex his biceps. Bench presses are not the reason for the pop.

"Two or three days before the first homer [Friday], I hadn't worked out and I haven't been in there since," Theriot said. "I'm not going back in."

Joshua told Theriot that when he played, weight lifting was taboo.

"[Joshua's] advice weight-wise was swing the bat," Theriot said. "Practice the motion that's going to produce hits. That's something that myself and Micah [Hoffpauir] and [Mike] Fontenot and Geovany [Soto] all do. We all swing the bat."

Joshua, in his fourth year at Iowa, has been a hitting coach since 1984, and some of his pupils include Mike Piazza and Magglio Ordonez. What's the secret? It's something Joshua calls a "fuzz machine," which is basically a pitching machine that hitters use in the cage. The gauge is set at 86-87 mph, but for some reason, the ball appears to be coming at hitters at 105 mph.

The device is not for everyone, and neither Joshua nor Cubs hitting coach Gerald Perry force any of the hitters to use it. But there could be a line forming after seeing what's happening with Theriot.

"The cool thing is Gerald and Von are close and share stuff," Theriot said. "It's a perfect scenario for guys coming up to the Major Leagues to have the same message."

Outfielder Brad Snyder, who is currently one of Joshua's pupils, recently started using the machine. On Monday, he hit his sixth homer and a triple. Joshua, who batted .273 in his 10-year pro career, said the machine helps hitters improve their bat speed.

"If you see a guy who throws 95 [mph] and you take a 95 mph swing, you're going to be under the ball," Joshua said Tuesday from Des Moines.

He wants the hitters to slow things down to stay on top of the ball. The fuzz machine helps a hitter's timing, even though Joshua doesn't like timing mechanisms like leg kicks. Hitting to the opposite field comes naturally to Theriot. What the device has done primarily is teach him how to pull the ball -- and do it the right way.

Joshua likes to point to St. Louis' Albert Pujols as having a perfect swing -- quiet, wide stance, fluid -- and encourages the Cubs hitters to follow that. Does that mean Theriot will be hitting like Pujols?

"I don't think anybody can do that," Joshua said, laughing.

When Ordonez or Mike Cameron, two of Joshua's students, would have a bad day at the plate, the first thing they'd want to do is get to work with the machine. Theriot knows the feeling.

"Theriot's best swing is to right field," Joshua said. "He perfected that and it helped him get to the big leagues. Now, he's gotten stronger and he's smarter and he knows what he's doing."

"I'll continue to do [the drills]," Theriot said, "and we'll see what happens."