Impulse And The GMs: The Most Important Contributors To Pitching Velocity

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In the spring of 2019, we got a call from Kyle Barker, CEO and founder of Aeronautic an aeronautical engineering company in Little Rock, Arkansas.  Kyle’s son, Will had trained with us for several years, and Kyle was one of the closest friends of Minnesota Twins pitching coach Wes Johnson.  When Wes was the pitching coach at The University of Arkansas, Wes had a state-of-the-art pitching lab installed.  The lab included a mound with force plates embedded.  According to Kyle and Wes, the information gained was incredibly useful, but there was one problem.  The sensors in the mound tended to slip and required manual (and somewhat subjective) “scrubbing” of the data after each session.  This required up to thirteen hours of work per week and meant that the information could not be shared with the athlete in real-time.  Wes asked Kyle if he and his engineers could solve the problem.  Kyle accepted the challenge, went “all in” and diverted his team of brilliant scientists from the task of building airplane and space ships to designing a mound with force plate sensors that didn’t slip.

After several months and many challenges, Kyle and his team solved the problem and produced the first-ever Newtforce force plate sensored mound linked to real-time 200 fps video.

That brings us to the call from Kyle.  He asked if we would consider beta testing the mound and creating training protocols to make sense of the data.  After about a nanosecond of consideration, I said yes.  Kyle personally delivered the mound in mid-July and our team got to work.  Initially, we kind of just wandered around in it ,trying to find some form, shape or meaning in the information.  After a month or so, our Director of Player Development, Wes McGuire, and our Director of Analytics, Jordan Rassman began assimilating the data.  They recorded the data from the force plates combined with Track Man readings and began to study them.  First, they looked for linear relationships between pitchers’ velocities and any of the 22 force plate metrics we had agreed to investigate.  Obviously, they found none.  Then we ran the data through the same XG Boost Machine Learning Algorithm that had allowed us to rank the attractors in our dynamic systems theory model of pitching.

After studying the data from over 500 students, the following are the results fo what we found.

This research afforded us an even deeper appreciation of one constant truth: There are a lot of ways to throw hard. There are not a lot of ways to throw hard AND safely for a long time, and stability in the back leg is at the center of both.

Identifying and ranking the attractors in this manner was the first step in our research and was a giant leap forward toward developing a formula for individualizing workload under the dynamic systems model.

We took the data from the attractor importance study and used it to create an algorithm that weights a collection of variables that contribute to readiness for increased workload. We put that into an app using the algorithm to create an overall ARM Readiness Score. As far as we know, the Arm Readiness Manager (ARM) is the first tool that individualizes workload recommendations based on the most relevant factors available. The overall scale is calculated an expressed on a 0-100 scale. The higher the score, the more likely it would be that player is prepared for an increased volume of throwing.

So, let’s say you’re a college or pro coach, and you’re heading into a weekend series. If you have 4 or 5 guys in the 80-100 range, 4 guys in the 50-80 range, and another 4 in the 30-50 range, you would expect to distribute most of your innings to the guys with the highest scores. After the series, you can drill down into the specific reasons for the low scores and through SAVAGE training, you can bump them up to prepare for the next series.

NewtForce Analytics

The next phase of our research was to collect, categorize, and analyze the NewtForce data to see if any further significant relationships could be found. We looked at force plate readings through the prism of our attractor-based biomechanical model and examined twenty-two different items for their importance in predicting velocity. The following diagram depicts a hypothetical force plate reading illustrating data points we looked at and the variables we investigated.



First, we’ll provide a little orientation to the landscape in the graph. 

The green line represents Z force, which is the force directly into the ground.  The red line is the Y axis.  Force directed behind the pitcher is considered “positive” Y and negative Y is toward home plate.  X force, or side to side movement is expressed in the blue line.  Positive X is to the right and negative X is to the left.  The initial upward curve of the green and red lines are indicative of back leg forces.  When the red line dips below the zero line the athlete’s weight has been transferred to his front leg. When the and red line and green line peak for the second time, the front leg has reached full weight-bearing.

With the data normalized for the weight of our subjects, the XG Boost algorithm revealed the four most important data point for predicting velocity were:

  1. Impulse
  2. Lead Leg Peak Y
  3. Time of Transfer Peak Z to Peak Z
  4. Lead Leg Negative Y Return to Zero

1)  Impulse the (orange shaded area) is technically the integral of the Y curve from zero, when the athlete starts moving down the mound to when it crosses zero and heads negative and force is transferred to the lead.  Impulse is calculated by multiplying the amount of force the athlete produces toward second base by the amount of time he pushes before crossing the zero line. For example, if the athlete pushes backward at 100 pounds and holds that load for 0.5 seconds, his impulse would be 50.

2)  Lead leg Peak Y is self-explanatory and represents the amount of force the lead leg is applying toward the plate.

3)  Time of Transfer peak Z to Peak Z is a timing metric that describes the rate at which the back leg Z force is transferred to the front leg Z.  

4)  Lead leg “Negative Y Return to Zero” is the time from Lead Leg Peak Y to the return to the zero line.  Some refer to this as the “clawing” or “blocking” action of the lead leg.  We call it swing leg retraction and Return from Negative Y.

Now let’s dig into each of the four contributing variables:

First, we note that in our most high-velocity pitchers the back leg Z curve and the back leg Y curve are usually relatively proportional.  When this happens, we can assume the athlete is pushing down into the ground and backward with the same ratio of force.  Symmetrical back leg Z and Y forces infer co-contraction of the muscles of the back hip. 

A key to improving velocity is to expand the area below the impulse curve.  There are two possible options for increasing impulse. 

You can push hard off of the rubber.  In doing so, you might cause the Y curve to spike upward, but there is a limit to how high you can get it to go.  Also, a disconnected/forced  forward move can be an impulse robber.  

A better way to expand the impulse and thereby improve velocity is to ride a co-contracted back hip,  holding a hinged load of the gluteus medius and gluteus minimus (we call them the GMs).

When the leg is non-weight bearing, and the hip is in neutral, the gluteus medius and minimus serve as abductors of the hip.  The picture on the right shows the pelvis tilted anteriorly 90 degrees.  When the hip is hinged to around 45 to 55 degrees, the fibers of the GMs are oriented to abduct and externally rotate the hip.

When the hips are hinged, the back leg is in a weight-bearing position, and the lead leg is lifted, the GMs are vital for holding the lead leg side of the pelvis above the back leg side.  In physical therapy, it is widely understood that weakness in the gluteus medius and minimus makes it difficult to stabilize the pelvis during the gait cycle.  When the opposite leg is lifted, a weak gluteus medius allows the pelvis to drop.  In my early years as a PT, the most common surgical technique for total hip replacement was known as the “posterolateral approach.”  During a posterolateral hip replacement, the gluteus medius was detached at its insertion on the femur by carving out a small flake of bone at its attachment point.  The gluteus medius was laid to the side and the procedure was completed. After the hip was replaced, the surgeon put the GM back into its normal position and allowed it to heal over the next six weeks like a fracture.  Because the patient was unable to bear weight on the involved leg during that six weeks, the GMs became weak and atrophied. Until the GM was strong enough to support the pelvis and prevent contralateral hip dropping.  The patient tended to walk with a distinctive, limp known as a Trendelenberg Gait in which, at full weight bearing on the involved limb, the patient would lurch his trunk to the side to compensate for the dropping of the pelvis on the non-surgical side.

Keeping the GMs at optimal length and the back hip muscles co-contracted holds the pelvic tilt and expands the amount of time the athlete can create a positive Y force.  Delaying the leveling of the pelvis expands the impulse and sets in motion a sequence of mechanical efficiencies that all contribute to velocity.

Another essential influencer of velocity is the time of Z to Z transfer.

Z-to Z transfers represents the speed of transfer from the back leg to the front leg.  Delaying the leveling of the pelvis by co-contraction of the back leg GMs and other muscles around the hip allows a rubber band-like stretch in the lower abdominals that, when suddenly released, catapult the body, the arm, and the ball forward.  If the pelvis remains in a neutral position, or if the leading side is lowered too soon, the speed of Z to Z transfer is significantly dampened.

Peak lead leg Y is the by-product of the efficiency and explosiveness of the back leg impulse and Z to Z transfer.  Peak Y force is actually the result of the athlete pushing hard into the ground to decelerate the center of mass. In elite throwers, Y force is automatically initiated by two innate reflexes known as the “crossed extension reflex” and the “stumble” reflex. There is no need to intentionally “block” the lead leg, and doing so may disrupt the synergy of the remainder of the delivery.

Finally, the rate of return to zero from peak negative Y shows the lead leg retracting and pulling backward to facilitate back hip rotation into late launch.

Many people have considered the relevance of this “clawing action,” but it is important note that intentionally “blocking” the lead leg can be corruptive as it can force the pelvis to tilt anteriorly, compromising lumbar and abdominal stability. 

Consciously “Blocking” the lead leg is a movement efficiency killer.

Interestingly, of all the possible velocity contributors we studied, the least important was stride length.  For years, some “experts” in baseball training world have insisted on reductionist concepts like, “the stride should be 120% of the height of the body” and “mass = gas!” 

The length of the stride is a product of the duration of the ride. And that duration or distance is different for every person.

According to the data from our force plate studies, mass is important for velocity up to about 180 lbs. 

After that, the body organizes itself and it really doesn’t matter how much you weigh.  For example, weight 210 pounds doesn’t make you more likely to throw harder than if you weigh 180 pounds.

It’s time we stop looking at pitching through a reductionist lens. 

The human body is a complex system and pitching is a complex movement.  There are no linear relationships in pitching.  To understand and find order in the chaos, we must turn to mathematics and look at the pitching motion through the lens of Dynamical Systems Theory. 

So let’s get back to impulse. 

Our XG-Boost machine learning algorithm suggests that expanding the area under the curve to the right of the current impulse metric is a highly recommended strategy power, synchronization for velocity enhancement. The impulse curve can be expanded by learning to hinge and co-contract the gluteus medius and gluteus minimus, thus keeping the pelvis elevated momentarily. This delay allows the athlete to take advantage of the elastic and mechanical properties of the back hip musculature. Expansion of impulse accelerates the time of transfer of back leg Z to front leg Z force. It also increases the lead leg peak Y force as the athlete braces against the ground with the landing leg and, finally, it enhances the return to on the lead leg. In essence, the pitcher’s impulse is the first domino that sets an entire downstream process in motion.

As it turns out, nearly all of the the lower-half efficiencies the Ranch process has considered to be disconnections are impulse killers.  Either through reciprocal inhibition or by removing the GMs from optimal length, these movement patterns disable or suppress GM activity and thus become significant impulse and velocity killers.

Below is a brief analysis I did on two pro trainees (both first-round draft picks) at the Ranch.  It explains more clearly how we use the information gathered from the Newtforce ® mound. It also shows clearly, the dangers of the intentional lead leg block. With Logan and Nick’s permission, I will share the video.

In just under two weeks of training, Logan has been able to significantly improve his movement pattern and has seen a 2 mph uptick in velo and the elimination of elbow pain. How did he do it? SAVAGE training.

SAVAGE is an acronym for Specific Adaptation thru Variability and Goal-Directed Experience. When we have an athlete with an unstable attractor, we infuse targeted SAVAGE training experiences into every facet of the his training (warm up, mobility, power building, strength training, skill work, and recovery).

One of the fundamental precepts in our SAVAGE training process is this:

If you want to stabilize an unstable attractor, make it more unstable. Perturbing the dynamic system with instability encourages the body to self-organize stability.

To change a movement, you have to change the mover. To stabilize the back leg (thereby increasing impulse) the athlete must have enough mobility to get into a position that optimizes the length-tension relationships in all of the muscles surrounding the hip. Then he must subconsciously find isometric co-contraction of all of those muscles to remove muscle slack so that he can amplify his ability to produce power, control his body, and protect his joints (UCL and labrum included). Anatomically, most people find optimal length in the hip muscles when their hips are hinged,, their butt is behind their heel, their knee is not forward of their toe, and the lead hip is higher than the trail hip.

Here’s an example of using variability (or unpredictable load) to encourage self-organization of stability by optimally lengthening the GMs and then co-contracting all the muscles surrounding the hip.

After feeling this movement for a while, the athlete would immediately progress to the mound to throw a pitch. This is a concept we at the Florida Baseball Ranch® and The Texas Baseball Ranch® call “blending.” You’d be amazed at the speed and quality of the results you can get by using The SAVAGE training approach to implicitly encourage self-organization of attractor stability.

We’ll be joining “forces” so to speak with Kyle Barker and Newtforce at the ABCA Convention in Nashville.  Kyle will have a force plate mound in our booth and we’ll be demonstrating and interpreting data all weekend, so stop by and see us in the exhibit hall.  

If you’d like to join us for the most sophisticated and highly effective process in the baseball training industry, call our CFO/COO, Amy Marsh at 866-787-4533 or click on one of the buttons below to learn more about how to engage our services.

Randy Sullivan, MPT, CSCS
CEO, Florida Baseball Ranch

For more information on the revolutionary Newtforce mounds and hitting pads, contact Kyle Barker by emailing him at KBarker@aeronautique.us or call him at 501-749-9116

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