Thank Magnus: Physics defines softball’s signature pitch

Thank Magnus: Physics defines softball’s signature pitch

If you ever have a free afternoon, head over to the softball field on the west end of the South 40. It doesn’t matter if it’s cold or windy or a little wet. Suck it up because you’re going to witness something neat. With any luck, you’ll see her – Annie Pitkin – the righty ace of the Washington University softball team.  Tall and thin like a whip, she’s taken advantage of a quirk of physics to perfect her signature pitch: the rise ball.

Hands together, right foot on the rubber, left foot behind, she raises her arms, rocking onto the back of her right heel. Pay attention because the next couple of moments are a flurry of limbs, leather and dirt. Her hands come apart, swinging back past her body at high speed. At its apex, her right arm—the one with the ball—is perfectly straight, just about perpendicular to her shoulder. Her right leg, which was back on its heel at first, is now planted, with its knee bent, ready to spring. Her left leg is straight back behind her, and her torso is bent at a 45-degree angle like a runner in mid-sprint. Just before you think her arm is going to pop off, it flies straight back through a downswing. She doesn’t release the ball; oh no, there’s another 360 degrees to go. Her arm comes through tracing a circle, still holding that bright neon orb while she leaps off the rubber with her right foot. She’s got to make sure to drag the toe. Otherwise, it’s an invalid pitch. Her left leg flies low, just above the ground, landing just inside the white circle around the mound—about 37 feet from the batter. Her hips fire through and her hand, now hurtling through the bottom half of the loop, releases the ball just behind her trailing leg. The whole motion from rock to release takes just over a second.

The motion is meticulously scripted, but when Pitkin lets go of the ball, physics takes over. The Magnus effect, a principle of aerodynamics, applies a force to the pitch. The law states that any spinning round object (like, maybe, a softball…) will create pockets of low and high pressure. That object is then pushed from the area of high pressure to low pressure. On a rise ball, Pitkin gives the ball as much backspin as possible, putting the pocket of low pressure above the ball, causing it to rise. The ideal version begins at the mid-thigh and ends up at the chest. Ball moves up, batters swing and miss and Pitkin fills her trophy cabinet.

“It definitely makes a lot of people look dumb when they swing at [her pitch],” teammate Hera Tang said.

But how does she throw such a baffling pitch? A lot of it is in the grip. She splits her pointer and ring fingers parallel along a pair of seams. Her thumb grips the ball below on another seam. As her hand comes through, she leads with her pinky—then she snaps her wrist clockwise— “like you’re turning a doorknob,” she says. That’s a little bit of an understatement. You’ve got to try and tear the damn thing off its screws. The more spin you give the softball, the greater the Magnus effect and the greater the rise.

Another crucial part of the pitch is when Pitkin distributes her weight on release. Unlike a baseball pitcher, who releases from basically the same point and derives motion solely from spin, softball pitchers vary their balance for different effects. On Pitkin’s rise ball, her weight is back, near her back leg, giving her an angle for the ball to travel up.

Both illustrations courtesy of Laura Ancona | Student Life

Both illustrations courtesy of Laura Ancona | Student Life

And it comes in fast. Although she doesn’t like the radar gun—it makes her tense up, she said—she’s hit as high as 66 mph. She probably sits closer to 60 mph, usually. Although this may not seem fast compared to the MLB, where guys regularly pump 94-mile-an-hour heat, remember that Pitkin’s pitching from 43 feet away from home plate. Do the math, and a softball batter has the same reaction time for her as a member of the St. Louis Cardinals throwing 93 mph—about 0.45 seconds. Pitkin is currently the NCAA Division III active leader in career strikeouts with 698, thanks to her pitch that defies gravity.

“My rise ball is my bread and butter pitch,” Pitkin said. “That’s what I throw when I’m down in the count; I can throw it for a strike, and I can throw it for a ball and get them to chase.”

The pitch may act cartoonish, but it is still hittable if you know it’s coming. That’s why Pitkin has two more pitches in her arsenal: a drop ball and a changeup.

Just as the rise ball breaks up, the drop ball breaks down. Pitkin grips the pitch like a fastball, pointer, ring and middle fingers across four seams. As she releases the ball, she snaps her hand up. When she lets go, her weight is over her front foot. Both the weight distribution and the wrist action gives the pitch as much topspin as possible. Remember the Magnus effect? Same rules apply, only the ball is going down, not up. The drop ball is actually the signature pitch of the Bears’ other starting pitcher, sophomore Maggie Clapp.

“They’re completely opposite pitchers, which is what kind of makes them so good back-to-back against the same team,” teammate Hannah Mehrle said.

With a changeup, Pitkin holds the ball like a drop ball, except she tucks her pointer finger into the area surrounded by the big u-bend in the seams. Between the two extremes, her weight distribution is neutral. The release is what’s really funky. As her arm swings through, she leads with the back of her hand and flips up, kind of like she’s flipping a yo-yo out. The idea is that it travels straight like a regular fastball but comes in much slower and forces the batter out in front. Ideally, a changeup finishes at the batter’s knees or lower. God forbid you let one hang, it could become a 50 mph pinata.

All three combine to mess with the vision of the hitter.

“It’s really hard as a hitter to change planes,” Pitkin said. “If you have a rise ball and a drop ball and a pitch coming in on a flat plane…you’ve got three different planes you’re trying to hit with one bat.

But one person Pitkin probably isn’t going to fool is Mehrle. Mehrle currently leads the team in all three major slash categories 0.518/0.831/0.583.

Mehrle spent nine years as a pitcher before coming to Wash. U.—and now she can pick up on all the little tip-offs, like a torqued wrist, a difference in stride length. She fancies herself as a good rise ball hitter, and occasionally, she’ll step in against Pitkin for practice. It’s usually a 50/50 battle.

“Sometimes I do well, sometimes [Pitkin] does well,” Mehrle said. “It depends on the day.”

Her advice for hitting the rise ball is pretty simple.

“You just have to be able to get your hands on top of the ball and hit the ball down, instead of hitting the ball up.”

The big secret though? The rise ball doesn’t actually rise. Although pitchers and batters will swear on their life that this isn’t the case, in reality the Magnus effect doesn’t have a big enough impact to actually make the ball defy gravity. Instead, it only allows the ball to drop considerably less than a player would expect. Your instincts tell you that the ball is supposed to drop 12 inches—it drops three. Your brain thinks physics need not apply.

But Pitkin and others shouldn’t care if their best pitch is just smoke and mirrors. Pitching is about deception, and if your pitch can make rookie batters rub their eyes in disbelief, it’s probably a safe bet in a 2-2 count.

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