Youth Baseball Pitching Mechanics Analysis Across Age Groups

Written by David Besky, Information Scientist II

As referenced in our have a look at velocity measurements throughout the youth information now we have from our Driveline Academy athletes, we’re amassing information on a large pattern of youth athletes as they age, and are extraordinarily excited concerning the analysis alternatives that can open up.

In that evaluation, we thought of the distribution of metrics (pitch velocity, bat pace, and exit velocity) throughout our completely different age teams to get an concept of how these have a tendency to vary as athletes age (with the caveat that we’re evaluating completely different athletes throughout every group). Right here, we take an identical have a look at the biomechanics information we’ve collected by having all Driveline Academy athletes throw in our movement seize lab.

Movement Seize Lab

Our markered movement seize lab is a staple of our coaching applications with our highschool, school and professional athletes, and it permits us to trace physique segments with submillimeter accuracy. This permits us to exactly quantify how athletes are shifting—providing distinctive alternatives for participant evaluation and analysis into what distinguishes how the most effective athletes transfer.

When contemplating youth information, we see a reasonably broad vary of heights and weights for the 8-14 12 months olds in our information set. We do see athletes usually get greater as they age, however even inside a crew we see a large unfold when it comes to how large (with out lack of generality) a 12 12 months outdated is.

For this evaluation, we largely take into account joint angles and angular velocities, that are considerably agnostic to the burden distinction throughout age teams. That’s, we’re taking a look at how shortly an athlete’s joints are shifting, which (versus vitality/torque/momentum) isn’t instantly a perform of the athlete’s weight, so the numbers are naturally scaled to every athlete’s weight.

We had athletes mocap in November of 2020 after which once more in the summertime of final 12 months to get a test-retest comparability to trace their modifications. We repeated this course of with our elevated variety of athletes within the Academy this fall to generate extra baselines.

For this evaluation, we take into account solely the primary mocap from every athlete (we’re nonetheless processing most of the athletes from the autumn on the time of this writing). We selected to contemplate their first mocap in order that the pattern is minimally influenced by any coaching the athlete has performed with us. We see 99 completely different athletes between the ages of 8 and 14.

Mocap Participant Rely by Age

To get a common concept of what we’re working with, right here’s a have a look at the unfold of top, weight, and velo by age throughout this inhabitants.

Weight by Age
Height by age

Actions differ on common between youthful and older athletes. Listed here are a number of of the core metrics we often take into account necessary indicators of how an athlete is shifting, organizing them into decrease half metrics, arm motion metrics, and posture/core metrics.

Decrease Half

First, let’s check out the decrease half. We take into account three metrics: entrance knee extension angular velo at ball launch (a measure of the lead leg block); heart of gravity (COG) velocity (how shortly the athlete strikes their physique in direction of the plate); and stride size.

Entrance knee extension angular velo at BR is fairly constant on common throughout age teams. We do see older athletes transfer their COG extra shortly (which can be confounded by top, since a taller athlete will transfer sooner in the event that they transfer the identical distance relative to their top in the identical period of time as a shorter athlete).

Stride size (when taken as a proportion of the athlete’s top) permits us to have a look at this similar transfer whereas controlling for the athlete’s top. After we do that, we do see older athletes nonetheless stride longer, although the impact is a bit bit smaller than for COG velo.

Knee Extension Angular Velo at BR
Knee Extension Angular Velo at BR
Max COG Velo X
Max COG Velo X
Stride Length vs Age
Stride Size
Average Values for Lower Half Metrics for Each Age
Common Values for Decrease Half Metrics for Every Age

Arm Motion

Transitioning to arm motion, we usually take into account a pair positions at foot-plant: shoulder abduction (if an athlete has a low elbow or is mountain climbing it above the shoulders); shoulder exterior rotation (how flipped up the forearm is); and shoulder horizontal abduction (scap retraction). As well as, we’ll have a look at how a lot exterior rotation (layback) they get and the max elbow flexion (how a lot bend they get of their elbow) all through the supply.

The final major arm motion metric we regularly reference is elbow extension velo and shoulder inside rotation velo (which measure how shortly the arm is shifting in these two actions as they happen throughout the throw).

Shoulder Abduction at FP
Shoulder Abduction at FP
Shoulder External Rotation at FP
Shoulder Exterior Rotation at FP
Shoulder Horizontal Abduction at FP
Shoulder Horizontal Abduction at FP

For these touchdown positions, we don’t see a transparent development for development as athletes age—and any potential development could be very small relative to the variability we see inside every age group with regard to their arm place at foot plant.

Max Elbow Flexion
Max Shoulder Exterior Rotation

We see common max elbow flexion maintain fairly regular throughout the completely different groups, however do see a point of an upward development for shoulder exterior rotation (with every year of age, avg MER will increase by ~ 2 levels), although there’s loads of variability between athletes round that development line.

Max Elbow Extension Velo
Max Shoulder Internal Rotational Velo
Max Shoulder Inner Rotational Velo

We see a slight improve in common elbow extension velo and shoulder inside rotation velo as athletes become old. This improve might not be as massive as we’d anticipate, however the older athletes are greater, so even the identical velocities would correspond to extra momentum and vitality.

Common Values for Arm Motion Metrics for Every Age


Lastly, we check out hip to shoulder separation (at foot-plant and the max worth) and torso/pelvis rotational velos.

Rotation Hip Shoulder Separation at FP
Rotation Hip Shoulder Separation at FP
Max Rotation Hip Shoulder Separation
Max Rotation Hip Shoulder Separation
Max Torso Rotational Velo
Max Torso Rotational Velo
Max Pelvis Rotational Velo
Max Pelvis Rotational Velo

Right here we see that older athletes are inclined to have extra hip to shoulder separation (each at its max worth and at foot-plant, which we take into account to see how successfully they’re in a position to time up their max hip to shoulder separation). Wanting on the torso and pelvis rotation velos, we see them maintain regular throughout the age teams or drop off barely (which can simply be a product of how far more vitality is generated from the athlete being heavier relative to a slight drop off in rotational velocity).

Average Values for Posture/Core Metrics
Common Values for Posture/Core Metrics


In complete, we see that some metrics have a tendency to extend barely amongst our older athletes, comparable to their capacity to coordinate their physique to shift their weight down the mound, get hip to shoulder separation, and get into extra shoulder exterior rotation.

For HSS and exterior rotation, these tendencies might consequence, partially, from the bodily improvement of athletes, which permits them to get into and maintain a number of the deeper positions that we see our increased stage (school and professional) athletes use. This highlights an necessary level: athletes’ mechanics might replicate technical or bodily limitations. Particularly with youth athletes however with our older athletes as properly, exterior cueing and self-organization enable for athletes to work inside the constraints of their distinctive bodily traits to optimally obtain the aim of throwing the ball laborious, effectively and successfully.

Whereas we are able to determine potential areas for motion enchancment primarily based on tendencies we see throughout a big physique of throwers, completely different athletes may have completely different idiosyncrasies that can drive how they transfer optimally, as evidenced by loads of variability in motion methods deployed efficiently by the laborious throwers in our database, together with MLB arms and throws as much as 100 mph.

In relation to youth athletes, we’re delicate to emphasizing exterior targets that enable them to make use of what athleticism they’ve as they’re nonetheless creating coordination. We don’t need to rob them of that by making an attempt (probably futilely) to dictate a particular set of right mechanics that they might not be bodily outfitted to do properly at that time limit.

With most of the different metrics (lead knee extension velo, arm positions at foot-plant, torso and pelvis rotational velos), we don’t see a big distinction between the completely different age teams. That mentioned, it’s true that the handful of metrics thought of on this evaluation don’t totally encapsulate every little thing that’s happening mechanically, so there are components of coordination and the way athletes get into and out of positions that aren’t thought of right here. Nonetheless, these consistencies in mechanics counsel the significance of prioritizing getting bigger, stronger, and extra highly effective as a path to rising output, as that’s a notable distinction between the older athletes who throw tougher and the youthful athletes on this pattern.

There’s nonetheless quite a bit to discover throughout our youth movement seize information, comparable to questions like: Do athletes who throw tougher for his or her age show related tendencies as we see when evaluating tougher throwers in our school/professional inhabitants? Can we see decreased variability in mechanics on a throw-to-throw foundation for older athletes in comparison with youthful athletes? How does our energy evaluation information (from soar testing) relate to those mocap information, and do these relationships mirror what we see with our HS/school/professional athletes?

We hope to the touch on these in future items as we dig deeper into these information.


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