Hitting Biomechanics – Driveline Baseball

Bat Pace, Level of Contact, and Rotational Velocities

Since finalizing the hitting set-up in our movement seize lab (The Launchpad) in July of 2021, we’ve had a whole lot of hitters are available in for a movement seize evaluation, together with a number of MLB All Stars and high collegiate and professional prospects. On the time of writing, Driveline has collected biomechanical information on over 2,000 swings throughout a variety of participant expertise from excessive schoolers as much as a few of the greatest hitters within the MLB.

This provides us a wealthy and distinctive database to assist us reply the query: what separates the very best hitters on the earth from their friends?

Numerous books could possibly be written on all of the challenges we’ve encountered and the failures we’ve made getting thus far; nevertheless, from these classes we discover ourselves effectively positioned to leverage our rising database and the hitting biomechanics insights are starting to trickle in. So let’s check out just a few fast ones!

Blast Movement vs. Movement Seize

One of many coolest features of hitting movement seize is that we’re in a position to gather all types of high-fidelity, full sign information on bat traits in the course of the swing. For instance, we’re in a position to see what a hitter’s bat pace or assault angle is at any given level within the swing (see figures 1 and a couple of). This provides our trainers a full image of what an athlete is doing somewhat than needing to depend on discrete metrics at impression to deduce swing and path high quality.

Determine 1. Full sign bat pace information exhibiting how briskly the candy spot of the bat is transferring at each level within the swing.

Determine 2. Full sign assault angle information can provide a greater thought of a hitter’s bat path all through everything of the swing.

Utilizing instruments like Blast Movement bat sensors each day provides us speedy suggestions throughout a coaching session, however swinging within the Launchpad permits for better precision and element. A lot of the guesswork that comes from video could be eliminated, serving to our trainers extra exactly pinpoint what a hitter does effectively and what they should enhance. 

The precision of the lab additionally means we are able to acquire extra constant reads on issues like bat pace or assault angle and full sign physique + bat kinematics, whereas avoiding variance resulting from incorrect sensor placement. This final level could be seen by wanting on the variations in the usual deviations of paired bat speeds measured with Blast and our mocap lab. These variations could not look enormous at first look, however when you think about that these values have been calculated after eradicating any apparent misreads from Blast, the variations seem fairly eye-opening.

Desk 1. Bat pace averages and commonplace deviations (SD) measured each by the mocap lab (left) and Blast (proper).

Bat Pace

We’ve already talked fairly a bit in regards to the significance of bat pace in a number of blogs authored prior to now, and within the desk beneath one can see that our outcomes from the Launchpad present much more proof as to why that is the case.

Desk 2. Common bat metrics from our lab cut up up by enjoying degree.

We see that, on common, our professional hitters swing the bat just below 72 mph, which is about 4 mph sooner than our faculty hitters and virtually 10 mph sooner than our highschool hitters. Not surprisingly, our professional hitters additionally hit the ball about 6 mph tougher than our faculty hitters within the lab and about 12 mph tougher than our highschool hitters on common.

We will additionally see from the distributions beneath that there’s a lot much less variability in bat pace and exit velocity amongst skilled hitters when in comparison with each faculty and highschool hitters. The important thing takeaway right here is that as batters transfer up in enjoying degree, they need to swing the bat sooner and hit the ball tougher than a sure threshold.

Determine 3. Distribution of peak bat pace cut up up by enjoying degree. We see a a lot wider distribution of bat speeds amongst each faculty and highschool hitters when in comparison with skilled hitters.
Determine 4. Distribution of exit velocity cut up up by enjoying degree. Identical to with bat pace, we see a narrower distribution of exit velocities amongst our skilled hitters when in comparison with highschool and faculty hitters.

Level of Contact

HitTrax and related applied sciences outline POC as the purpose the place contact is made relative to house plate. Whereas this metric does present quite a lot of helpful info, it does have some limitations resulting from the truth that not each hitter stands in the very same spot within the batter’s field or has the identical size stride. This could make it a bit more durable to check one hitter’s POC to a different’s. So what if we have been in a position to measure POC relative to a hitter’s physique?

Utilizing our movement seize information we are able to use a hitter’s heart of gravity (COG) to find out how far out in entrance or deep within the zone contact is made relative to that hitter’s physique. We will merely calculate the gap between a hitter’s COG place and the place of the candy spot of their bat to get what we are going to discuss with as their MoCap POC (determine 5). 

Determine 5. How MoCap POC is calculated.

Each hitter is aware of the sensation of hitting a ball too deep within the zone or too far out in entrance and can have the ability to let you know that these totally different swings are going to yield a lot totally different outcomes. For instance, this can be a swing from our lab with one of many deepest factors of contact:

Determine 6. A swing with a POC of -6.94 cm. Contact is definitely made behind the hitter’s COG.

Evaluate that to a different swing from our lab which had the furthest POC in our database:

Determine 7. A swing with a POC of 83.18 cm.

These two swings are going to lead to a lot totally different spray and launch angles and, as we are going to see shortly, would possible have a lot totally different bat speeds.

As a result of hitting is so reaction-based and largely depending on the incoming pitch, we anticipate there to be rather more variation from swing to swing. Measuring POC relative to the physique provides us one approach to evaluate related swings throughout totally different athletes.

When POC throughout totally different ranges of play we see an attention-grabbing development the place POC will increase with enjoying degree. The plot beneath reveals the distribution of POC cut up up by enjoying degree.

Determine 8. MoCap POC by enjoying degree.

Highschool hitters are inclined to make contact virtually 12 cm (or about 5 inches) deeper within the zone relative to their physique when in comparison with skilled hitters. Nevertheless, this will not be a generalizable development that we’d observe outdoors of our lab. Throughout movement seize assessments, we arrange the pitching machine 45 ft from house at an ordinary setting of 65 mph. One potential rationalization is that it’s marginally simpler for hitters at larger ranges to hit in opposition to these settings than decrease degree hitters and, thus, why we see POC improve with enjoying degree.

Nonetheless, we see that, on common, POC will get barely farther out in entrance as you go up in enjoying degree. Whether or not this can be a results of us controlling the issue of the incoming pitch or not is tough to say, nevertheless it’s possible that this development doesn’t maintain in the identical approach in additional game-like settings at totally different ranges of play.

Why Energy Hitters Dwell Out In Entrance

Ask any hitter and most will let you know it’s a lot simpler to hit a house run to the pull-side than to the alternative area. Looking at POC and its relationship to bat pace provides us some perception into why it could be simpler to hit the ball tougher to the pull-side. 

Hitting a ball to the pull-side requires a POC that’s farther out in entrance of the physique than hitting a ball to the alternative area. This may possible lead to a barely larger bat pace than if contact was made deeper within the zone. Once we plot MoCap POC in opposition to bat pace we see that there’s a constructive linear relationship the place bat pace will increase with POC when evaluating swings from totally different hitters (determine 9).

Determine 9. MoCap POC vs. peak bat pace.

This relationship intuitively is sensible because the bat has extra time to speed up the farther out in entrance contact occurs. Once we management for a participant’s common bat pace and common level of contact – to additional tease out the anticipated impact if an athlete have been to make contact additional out in entrance on a few of their swings – we see that this development stays the place a rise in POC is related to a rise in bat pace.

Determine 10. MoCap POC above common measures how a lot farther in entrance/behind a hitter makes contact relative to their common POC throughout a given session. Bat pace above common measures how a lot larger/decrease a hitter’s bat pace is in comparison with their common bat pace for a given session.

Utilizing that relationship plotted in determine 10, an extra 10 cm (~4 inches) of POC corresponds with a rise of roughly 0.6 mph for that athlete. Now, this isn’t essentially to say that everybody ought to be making an attempt to make contact as far out in entrance as potential to maximise their bat pace. In actual fact, there are going to be trade-offs with making contact farther out in entrance corresponding to a better assault angle (see determine 11).

Determine 11. MoCap POC vs. assault angle.

Sequencing Effectively

Movement seize permits us to not solely monitor the motion of the bat throughout a swing, it additionally permits us to trace totally different segments of the physique and see how they might affect the swing. One of many extra widespread methods to find out how effectively a participant strikes throughout a swing is to take a look at how briskly and in what sequence they rotate their physique. We usually take a look at the angular velocity of the pelvis, torso, higher arm, and hand to get an thought of how effectively a hitter makes use of their complete kinetic chain to create bat pace. Ideally a hitter may have a sequence that appears one thing like this:

Determine 12. The kinematic sequence of the pelvis (purple), torso (inexperienced), higher arm (blue), and hand (yellow) reveals how every phase builds off the rotational velocity created by the earlier phase.

We see right here that the phase velocities peak so as as we transfer up the chain from the pelvis, to the torso, to the arm, and to the arms. On this approach, every subsequent physique phase builds off of the speed that was generated by the earlier phase. For extra context, the visuals beneath show precisely what we’re searching for after we speak about angular velocities of various physique segments sequencing effectively:

Determine 13. Pelvis angular velocity measures how shortly the pelvis (highlighted phase) rotates in the course of the swing.

Determine 14. Torso angular velocity measures how shortly the torso (highlighted phase) rotates in the course of the swing.

Determine 15. Higher arm angular velocity measures how shortly the higher arm (highlighted phase) rotates in the course of the swing.

Determine 16. Hand angular velocity measures how shortly the hand (highlighted phase) rotates in the course of the swing.

Shifting Quick = Hitting the Ball Tougher

Maybe unsurprisingly, a comparatively easy statement we’ve been in a position to make with the information we’ve collected in The Launchpad is that rotating sooner is correlated to swinging the bat sooner and hitting the ball tougher. The desk beneath reveals a handful of rotational velocity metrics and their relationship to each bat pace and exit velocity:

Desk 3. Correlations for various rotational velocities vs. bat pace and exit velocity. The values within the desk are Pearson Correlation Coefficients (often known as the R worth) the place a worth of 0 represents no relationship and a worth of 1 represents an ideal 1-to-1 relationship.

All six of those rotational velocity metrics are considerably correlated to each bat pace and exit velocity at contact. Thus, the sooner these segments rotate, the sooner the bat strikes and the tougher the ball is hit. 

Curiously, the connection between rotational velocity and bat pace / exit velocity will get stronger the additional one strikes up the chain (or towards the bat). So, it could be potential for an athlete to beat slower pelvis and torso rotational velocities with larger arm and hand speeds later within the swing to generate bat pace.

One other attention-grabbing takeaway from this desk is that max pelvis angular velocity has a weaker  correlation to bat pace and exit velocity than pelvis angular velocity at foot plant. In different phrases, it could be extra essential that the pelvis is transferring shortly as a hitter lands with their lead leg than it’s to max out pelvis rotational velocity at another level in the course of the swing.

To get a way of simply how briskly hitters in our lab are transferring, check out the desk beneath. In doing so, you’ll see that the correlations mentioned above appear to carry true when wanting throughout all enjoying ranges.

Desk 4. Common angular velocities of assorted physique segments seen in our lab, cut up up by enjoying degree.

Identical to with bat pace, we see that rotational velocities seem to extend with enjoying degree with bigger variations in arm and hand speeds.

What’s Subsequent?

With our preliminary foray into hitting biomechanics, we confirmed a few of the extra fundamental hypotheses associated to the basics of hitting. Higher hitters swing tougher, make louder contact, stay additional out in-front when hitting pitches of equal problem, and rotate sooner / extra effectively. With these truths supported, we’ll leverage The Launchpad to assist us examine questions and quantify mechanical traits we have been beforehand unable to. A major focal point in our future analysis shall be in understanding and quantifying what makes for an environment friendly and optimum bat path. Together with this we hope to study extra about how totally different mechanical attributes affect batted ball outcomes. Keep tuned for extra insights into hitting biomechanics as we dive deeper and deeper into the information!