Nine Home Runs, One Weird-Shaped Bat, and a Physics Lab That Burst the Bubble

Hold a torpedo bat and something immediately feels wrong. The barrel thickens not at the tip, where a standard bat rounds to its widest point, but several inches back toward the handle, giving the whole thing a squat, slightly aggressive silhouette: fatter in the middle, tapering oddly toward the end, like a piece of lumber that changed its mind partway through. When the New York Yankees walked onto the field in late March 2025 with bats that looked like this, and then hit nine home runs in a single game, the baseball world more or less lost its composure. A new weapon, people said. An unfair advantage. The shape of things to come.

The shape was certainly new. Whether it was an advantage is a rather different question, and it’s one that three sports engineers have now tried to answer in a laboratory for the first time.

The basic idea behind the torpedo bat’s redesign is logical enough, once you understand what the barrel of a bat is actually doing. Wood bats have a sweet spot, a region of the barrel (typically around five or six inches from the tip) where impacts lose the least energy to vibration. Hit the ball there and it flies. Hit it an inch or two toward the handle and the bat hums unpleasantly in your hands; the vibrations carry energy away from the ball, costing you distance. The torpedo design, developed by bat maker Marucci with input from Yankees hitters, moves mass from the low-performing tip of the barrel toward that sweet spot, widening and weighting the region that matters most without adding overall weight to the bat. In principle: more hitting surface where you actually want it, less where you don’t.

Whether that principle translates to any real-world difference in how hard the ball gets hit is what Lloyd Smith at Washington State University, Alan Nathan at the University of Illinois, and Daniel Russell at Penn State set out to determine. Their findings will be presented at the International Sports Engineering Association conference in Pullman, Washington, in June.

The team commissioned four maple bats for the study: two built to standard MLB specifications and two in the torpedo profile, all matched to the same total weight and nearly identical swing weight (technically, the moment of inertia about a point near the handle). The bats were actual duplicates of bats used by a specific major league player in 2024 and 2025, though the player’s identity wasn’t disclosed. To measure performance, the researchers fired baseballs from an air cannon at 100 mph at each stationary bat, then used light gates and high-speed cameras to calculate how much energy the bat returned to the ball. This ratio, the ball-bat coefficient of restitution, or BBCOR, is perhaps the most direct measure of how well a bat performs at any given impact location along the barrel.

“Wood is wood,” Smith said, and the data bear him out, more or less. Across 288 measurements on the four bats, the torpedo and standard designs produced nearly identical peak performance. The efficiency of the collision at the sweet spot was the same. The shape of the performance curve along the barrel was the same, a smooth parabolic rise and fall. The main difference: the torpedo bat’s sweet spot sits roughly half an inch closer to the handle than on the standard bat, which is exactly what the design intended.

That shift matters, but not in the way the breathless post-game commentary suggested. Because the bats were matched for swing weight (meaning a blindfolded batter could not feel any difference), that inward sweet-spot shift comes at a cost: a ball struck at the torpedo bat’s optimal zone travels slightly slower than the same ball struck at a standard bat’s optimal zone, because the barrel is moving a touch slower at that position. Hardly the revolution anyone was advertising.

There is, however, a more interesting result buried in the data. One of the two torpedo bats, designated T156, behaved differently from its twin. Despite having the same profile and the same weight, T156 had vibrational properties that were slightly different from the other three bats, and those differences translated into a measurably wider sweet spot: the region where the BBCOR exceeded a reasonable performance threshold was 2.7 inches for T156, compared to 2.4 inches for the standard bats and the other torpedo. A wider sweet spot is genuinely useful, because batters don’t always make contact where they’d like to.

The catch is that this advantage seems to have come from natural wood variability rather than from the torpedo shape itself. Wood, even carefully selected maple, is not a uniform material; its density, stiffness, and vibrational characteristics vary from tree to tree and log to log. The two torpedo bats, cut to identical specifications, ended up with different inertial properties and different bending frequencies. T153 behaved almost exactly like a standard bat, just shifted half an inch along the barrel. T156 didn’t, but the researchers are still working out why.

This raises a genuinely awkward question for anyone who attributed the Yankees’ nine-home-run game to their equipment: how much of the torpedo bat’s apparent effect was bat shape and how much was simply the lottery of which pieces of maple happened to be cut that way? The science cannot yet say. Smith has spent two decades studying bat performance and has watched similar debates play out before, ash versus maple being perhaps the most prolonged; his view is that wood just doesn’t give engineers much to work with.

Still, the torpedo story isn’t quite over. The research team’s simulations suggest that batters who prefer to make contact closer to their hands, whether by habit, pitch location, or swing mechanics, could plausibly benefit from the torpedo profile’s repositioned sweet spot, even if the absolute power numbers are comparable. And the T156 result, with its broader effective hitting zone, has prompted the researchers to start modelling the vibrational physics more carefully, running computer simulations to understand what specific combinations of wood density and bending modes might produce that wider peak. If those simulations identify the right characteristics, it may eventually become possible to select or construct bats with reliably wider sweet spots regardless of shape. That’s a more modest story than nine home runs in a night, but it might be more durable.

Wood, it turns out, is still wood. What changes, perhaps, is how precisely we can choose which piece of it to swing.

Source: Nathan A, Smith L, Russell D. Studies of the Torpedo Bat. ISEA 2026, The Engineering of Sport 16, Washington State University, USA, 1 to 4 June 2026. https://baseball.physics.illinois.edu/ISEA2026-Torpedo-v7.pdf