Instruction vs Intent Part 2: Uphill vs Downhill Swing Plane

A couple weeks ago I posted an article discussing the advantages/disadvantages of hitting with a closed front side in response to an MLB Network segment where Josh Donaldson explained his philosophy on hitting and swing mechanics. In this second article on the difference between hitting instruction and intent, I would like to tackle one of Donaldson’s other points in the video – that a “downhill” swing plane should never be taught to young hitters and that young players, when told to hit down through the baseball, should ignore their coaches.


First, to be sure that everyone is on the same page, we need to start by defining some terms. Luckily for us, one of the greatest minds in the field of baseball physics works right down the road from Warbird Academy at the University of Illinois Urbana-Champaign and has already done much of the leg work. Dr. Alan Nathan devotes his research to studying the effects that things like ball spin, trajectory, bat angles, etc. have on the game of baseball.


Most relevant to us is a two-part article titled “Optimizing the Swing” that Dr. Nathan authored for delving into exactly what we will discuss here (albeit on a much deeper level). For simplicity’s sake, I will be cherry-picking a few select terms and definitions from Dr. Nathan’s article but if you have the time and the curiosity, you should really read his piece in its entirety: Part 1 and Part 2.


For our discussion, we really only need to define two main concepts:


1.  Descent Angle – This is the angle of the pitch, relative to the ground, as it descends from the pitcher’s hand to the batter. In Dr. Nathan’s studies, this was 6 degrees for a fastball and 10 degrees for a curveball.


2.  Attack Angle – This is the angle of the bat path, relative to the ground, as it strikes the baseball. In this article, anytime I say “swing plane” you can think “attack angle” and vice versa.


NOTE: There is a third variable that Dr. Nathan explains in the article called “offset,” which is the vertical distance between the center of the barrel and the center of the baseball at contact. I’m omitting the mention of offset in this discussion to keep things simple but, again, check out Dr. Nathan’s article for an in-depth explanation.


Now, before things get too complicated, let’s pause and address the first big question:


“What is the best swing plane? Uphill, downhill, or level through the ball?”


Well, first of all, understand that when we talk about a “level” swing plane, we are speaking in relation to the descent angle of the pitch, not the ground. So, for a fastball with a six degree descent angle, a corresponding attack angle of six degrees would be considered “level.” Graphically represented, each of the three planes would look like this…




If you’re thinking to yourself, “that downhill one looks stupid,” you’re right. Unless you have a passion for short, slow walks from first base back to the dugout, you should never really swing “down” at the ball. That means the superior swing plane is either level or uphill (or, as Dr. Nathan calls it, “the homerun swing”).


Here’s the short version: Dr. Nathan looked at Batting Average on Balls in Play (BABIP) for both a level swing and an optimal “homerun swing” attack angle of about 24 degrees. The verdict? BABIP was nearly identical for both swing planes but the probability of hitting a homerun with a level swing is FAR less than with an uphill swing plane.


So, there you have it! Donaldson was spot on. If you want to be a good hitter, swing with an uphill plane. You’ll have just as high of an average as those dumb level-swingers but you’ll hit more bombs. Right?




Well, no.


Guess what variable Dr. Nathan (knowingly) omitted in his first analysis. Timing.


His initial calculations assumed a consistent, equal contact location. So, unless you are some kind of cyborg who can contact the pitch in the same place every time you swing, regardless of variations in speed and location, this has some important implications for you.


Nathan examined the effects of timing by comparing two hitters, a level swinger and an uphill swinger, who were both equally late on a pitch by three milliseconds (fun fact: an eye blink takes about three hundred milliseconds). In this scenario, the level swinger would hit the ball almost identically to how he would hit it if he had arrived perfectly on time. The uphill swinger? Well, he would most certainly be out. The reason is pretty obvious.


In a level swing, the barrel of the bat exists on the same plane as the pitch which makes it very forgiving in regard to errors in timing. In an uphill swing, the bat and ball exist on different planes and, therefore, must arrive at a very specific location at the exact same time to optimize the result of the swing. This is very, very difficult to do. Especially when you consider that the guy standing on the mound is actively trying to prevent you from being on time by mixing pitches, speeds, and locations.


So, when you are teaching young (under 18) hitters how to swing, you don’t want them to think about swinging uphill through the ball for two reasons:


1.  Young hitters are really bad at being on time.

2.  Young hitters generally aren’t strong enough to hit homeruns, even if they are on time.


Rather, you want young hitters to swing level through the ball to maximize their ability to hit hard line drives and help combat their inevitable timing miscalculations.


“Ok, Lucas, I guess that makes sense but you said ‘level’ not ‘downhill.’ Where did the whole ‘swing downhill’ thing come from?”


Cuing someone to swing downhill is simply a tactic to help level out a hitter who is dropping their back shoulder, or hands, or barrel, which is something that a lot of young hitters do. This goes back to the concept of “instruction” vs “intent” that I talked about in the last article.


Often an instructor will cue something (e.g., “Be downhill!”) knowing full well that it’s not exactly what they want their hitter to do. Rather, their intent is to bring the hitter towards a happier medium (e.g., “Be level!”). If a coach or instructor that you trust is telling you to be downhill through the ball, they are probably seeing you collapse on your backside or have an attack angle that’s too steep.


Don’t like being told to be downhill? That’s fine. But, ask your coach why they are telling you to do that. Don’t just ignore them. I bet there is another cue they can give you to get the desired result. Personally, I can think of roughly a bazillion other cues I use in replacement of “be downhill.” It all depends on the hitter and what’s actually causing their poor attack angle.


I want to finish with an anecdote that demonstrates just how careful instructors must be with the verbiage they choose when teaching young hitters.


One of my best students – now a senior in high school, we’ll call him Quark – went to a baseball camp at a local university where the head coach of the baseball program was explaining (accurately, mind you) the concept of uphill swing planes and how hitters should never be level with the ground as they swing but rather just slightly uphill to match the plane of the pitch.


As Quark left camp that day he was walking behind a group of his peers who had been moved by the speech:


“Wow, I’ve never thought of it that way.”


“Yeah, my coaches have been wrong this whole time!”




When Quark arrived at camp the next day, it was a flurry of pop-flys and foul balls. Why? Well, young hitters don’t deal well with subtlety or nuance. After hearing that a slightly uphill swing can optimize contact and power, hitters were dropping their hands and back shoulders in an attempt to form a more perfect plane. The result was catastrophic to their swing mechanics and highlighted their inability to arrive to the ball on time.


The moral of all this? An uphill attack angle truly does foster more homeruns and can, if timed correctly, result in a high average as well. But, it’s only suitable for a select number of hitters.


Are you small? Not very strong? Super fast? Then, an uphill attack angle isn’t going to make you a better hitter.


Are you enormous? Slow? Strong like bull? Then, an uphill swing plane can help you leverage your strengths as a player.


Ultimately, young hitters who aren’t yet fully developed need to be taught how to maximize their barrel’s presence in the zone via a level swing plane. This helps them square pitches up the most frequently and allows them the opportunity to be successful hitters as they learn how to appropriately time up different pitch types and different pitch locations.


Hopefully these articles have helped to un-muddy the waters a bit. Just remember, while the core concepts of hitting tend to remain the same, the approach to these concepts must be individually tailored to a hitter to address both their level of development and their strengths as a player. Though it may seem like common sense, a 13-year-old softball player and a 3-time MLB All Star shouldn’t necessarily take the same approach to hitting.


Thanks for reading!

Lucas Cook

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