Daddy Hacks or: The Lone Peril of Swinging Too Exhausting

I can’t probably start to cowl all the superb work regarding Statcast’s new bat monitoring knowledge. Now as a lot as ever, it’s vital to assist your native Baseball Prospectuses, PitcherLists, Baseball Americas, FanGraphses and freelance Substack writers. We transfer shortly in these components. There’s a lot evaluation to devour, all of it excellent.

When confronted with this new knowledge, one among my first instincts was to see which metrics from different areas of sabermetric evaluation might be replicated throughout the bat monitoring framework. Enter Ninetieth-percentile exit velocity (90EV); it’s a robust shorthand metric that distills loads of details about the highest finish of a hitter’s exit velocity distribution right into a single quantity. It’s not good, and different metrics outperform it, but it surely’s straightforward to see the way it has grow to be standard in modern evaluation, particularly in prospecting and scouting circles.

So I appeared to 90EV for inspiration with respect to bat velocity. I assumed bat velocity, being a major enter to exit velocity, would exhibit related strengths in characterizing a hitter’s distribution of bat speeds by consolidating probably the most essential speeds right into a single worth. Certainly, parsing bat speeds into deciles seems to work rather well:

Common exit velocity will increase linearly with bat velocity. So does contact high quality (xwOBA on contact, or xwOBAcon) and barrel charge (Barrel%). All of those traits meet expectations. What defies expectations, nonetheless, is that contact charge (Contact%) spikes for a hitter’s prime 10% of bat speeds. Whereas bat velocity correlates positively with whiffs (that’s, extra bat velocity sometimes means extra whiffs), the typical hitter’s quickest swings evidently produce extra contact, not much less, and by a considerable margin in addition. That’s an incredible collective feat. It’s just like the numeric equal of “seeing seaside balls.”

There’s extra to this than meets the attention. Why is that this potential? Let’s view the predicament via the lens of physics. Do you bear in mind physics? One factor I bear in mind — along with spending an inordinate period of time throughout a number of days with my pal Kevin making an attempt to bounce an empty plastic apple juice bottle on its facet to get it to land upside-down on its cap — is that drive equals mass instances acceleration. Not velocity, however acceleration. The standard swing begins at an preliminary velocity of zero and makes contact at a closing instantaneous velocity of X (on this case, “Bat Pace”). To achieve X mph from 0 mph, the bat should speed up. How a lot the bat accelerates determines how a lot drive the hitter imparts upon the ball. And what’s a hitter’s major job if to not impart drive upon an unsuspecting, unassuming baseball?

The bat monitoring knowledge from Statcast doesn’t embrace mass (i.e., the burden of the bat), and we barely have acceleration. At finest, we should make a flawed assumption that bat acceleration is fixed all through a hitter’s swing. (We make the identical assumption for a pitch’s motion via area — how dangerous might or not it’s? Possibly don’t reply that query.) I cobbled collectively some crude acceleration estimates primarily based on bat velocity and swing size utilizing my extraordinarily time-withered recounting of Eleventh-grade physics as a Martinelli’s bottle tumbled via my mind. Villain origin story apart, what relevance is acceleration if we have now closing velocity? Particularly, we will use acceleration to diagnose variations in seemingly equivalent bat speeds. Think about two swings with bat speeds of precisely 75 mph, but one swing is just seven toes lengthy, the opposite eight toes. We are able to assume the previous swing needed to speed up extra shortly throughout a smaller distance to achieve the identical instantaneous velocity on contact because the latter.

So as a substitute, how do a hitter’s bat acceleration deciles correspond with numerous measures of manufacturing? A lot otherwise:

In shifting from the penultimate decile to the highest decile, the league-average exit velocity plateaus at 86.4 mph (moderately than persevering with to extend linearly). Contact charges peak nearer to someplace between the Sixtieth and Seventieth percentiles, as does Statcast’s new square-up share (Sq.-Up%). Barrels peak under the Ninetieth percentile, as does Statcast’s new Blast charge metric (Blast%), in addition to our tried-and-true xwOBAcon. The feel of assessing swing efficacy (via the point of view of a single bat monitoring measurement) has modified fully.

All of which is to say that daddy hacks — true swing-out-of-your-shoes daddy hacks — maybe aren’t one of the best ways for a hitter to optimize his offensive manufacturing. Which isn’t to say that daddy hacks aren’t good, productive swings — they’re nonetheless among the many most efficient swings a hitter could make, and a hitter should err on the facet of an excessive amount of acceleration moderately than not sufficient — however it is a query of optimization, not magnitude.

What, then, is one of the best ways to optimize? What’s the best mixture of bat velocity and bat acceleration, utilizing this unsophisticated percentile framework? It’s someplace within the red-highlighted space under, which is often not the place a hitter maximizes his acceleration:

It is the place he maximizes bat velocity, however via an extended swing that permits extra time to speed up (at a barely decrease charge of acceleration) to its most velocity. That’s not one thing you possibly can glean from bat velocity alone. As such, top-10% bat velocity as a 90EV-equivalent metric merely doesn’t seize the knowledge we would like it to seize, not less than not in its entirety.

The answer to the issue of optimization vis-à-vis contact high quality for any hitter, no matter dimension and energy, is to reduce swing size for any given bat velocity (purple = excessive common exit velocity, blue = low).

To be clear, lengthy swings aren’t dangerous; in actual fact, an extended swing (in distance, not time) tends to indicate extra distance throughout which to speed up, which naturally creates extra bat velocity. You may truly see that longer swings are related to increased bat speeds and better exit velocities. But when a hitter can obtain the identical bat velocity with a shorter swing, he’ll inherently generate extra acceleration.

Presumably not all hitters take daddy hacks on the similar frequency. On the similar time, I can not with any confidence attest to which hitters take extra daddy hacks than others. Understanding what we learn about them, I doubt Steven Kwan takes anyplace close to as many daddy hacks as Javier Báez. For this reason I’ve taken care to check with league averages and “the standard hitter.” At what threshold above a hitter’s common bat velocity do contact charge and high quality begin to degrade? Does that threshold change from hitter to hitter?

As for daddy hacks themselves, each bat velocity and acceleration correlate immediately with ball-strike depend. Bat velocity and acceleration peak when the depend is most of their favor (3-0), and reduce steadily because the depend turns into much less favorable, with hitters’ slowest swings occurring in 0-2 counts. It’s in these advantageous counts that hitters probably do themselves a disservice (simply barely a disservice, however a disservice nonetheless) by taking daddy hacks moderately than taking just a little off it to make sure they sq. it up just a little higher — to make sure the chaos is in actual fact managed:

The perfect swings, then, look like people who enhance bat velocity via acceleration moderately than swing size, impartial of pitch location. I say “impartial of swing location” as a result of swing size correlates with lateral (east-west) pitch location, with inner-half pull-side approaches yielding longer swings. The red-and-blue jelly bean above exhibits that swing size is positively correlated with exit velocity, so it is sensible that pull-side swings yield excellent outcomes. They not solely make the most of a shorter outfield wall distance but in addition allow the hitter to generate extra bat velocity throughout an extended swing distance. Two swings with equivalent charges of acceleration will produce totally different swing lengths and closing bat speeds primarily based completely on the pitch’s location. This complete factor has been in regards to the swing — it’s primarily in regards to the swing — but it surely’s about swing choices, too, and the augmentative powers of these choices.

Bat velocity turns into dependable way more shortly than exit velocity, which by itself ought to shortly cement it into the analytical toolbox. Like every other metric, although, it nonetheless requires an immense quantity of context, lest we threat evaluating apples to oranges. Acceleration is a few of that mandatory context, and I anticipate that when we have now year-over-year knowledge, we are going to use it to diagnose accidents or spot indicators of decline higher than bat velocity by itself.

All stats are via Might 19.