During the summer of 2021, I was scouring the internet, seeking alternatives to the “sleeper stretch” in order to better compel shoulder internal rotation (IR) in overhead athletes. While the sleeper stretch had garnered high praise from the overhead athlete and physical therapy community for decades—it’s often considered a staple movement within many baseball and shoulder rehabilitation programs—a handful of new alternatives to address shoulder IR inefficiencies have begun to gain steam in recent years. In large part thanks to the contributions of the Postural Restoration Institute (PRI), it was starting to become clear that the cause of poor shoulder IR might not even be a result of the shoulder itself.
At the time, I was interning under the guidance of renowned Philadelphia-area strength and conditioning coach and educator Rob Rabena (who will always have my gratitude), and he steered me toward Las Vegas physical therapist (PT) Zac Cupples. Rabena noted that Cupples would be able to clearly explain that it is the rib cage that forms the base for our shoulder girdle, and our shoulder motion can be profoundly influenced by altering dynamics within the rib cage. Thoroughly impressed by Cupples’ explanation, I began hastily consuming more and more of his content before ultimately joining his mentorship program in 2022.
During our conversation for this interview, Cupples revealed a bit of wisdom that I continue to reflect on and seek to implement on a daily basis. When I asked how we, as coaches, can continue to improve our craft (in addition to making our athletes better), he said:
“It starts with cultivating your relationships and assembling a team around you comprised of individuals who are predominantly smarter and more proficient than yourself. It may sound counterintuitive, but this will ensure you are continually being pushed to enhance your own skill set, which can prove challenging if you are the smartest person in the room. Multiple heads are better than one, and you can advance your coaching mastery more rapidly if you are constantly engaging with others [who are] always willing to help nudge you in the right direction.”
(Improving your coaching) starts with cultivating your relationships and assembling a team comprised of individuals who are predominately smarter and more proficient than yourself, says @ZCupples. Share on X
Cupples graduated from St. Ambrose University’s Doctor of Physical Therapy program in 2011 and then went on to obtain both his Orthopedic Specialist Certification (OCS) and Certified Strength and Conditioning Specialist (CSCS) certification in 2013. He has been a PT clinical director, continuing education reviewer, and National Basketball Association (NBA) PT and Assistant Strength Coach. Despite his highly regarded academic and industry accolades, if you ask Cupples what experience he valued the most, he will enthusiastically point to his time in Indianapolis, when he interned for the legendary Bill Hartman at IFAST University. As the Illinois native’s admiration for Hartman has grown over the years, in a similar vein, so too has my admiration for Cupples.
Prior to embarking on this journey with Cupples, I was completely oblivious to the idea of posterior expansion versus muscle compression, sacral nutation versus counternutation, and rib cage dynamics, let alone the varying axial skeleton archetypes. While Cupples was able to cast light on crucial industry topics I was otherwise unfamiliar with, it was (is) his ability to unscramble otherwise ambitious topics and present them in a digestible manner that proved to be his most helpful quality.
Cupples’ ability to unscramble otherwise ambitious topics and present them in a digestible manner proved to be his most helpful quality. Share on XAt the conclusion of our May mentorship call, I sought to glean from Cupples serviceable insight that coaches and/or athletes can directly apply:
- Programming considerations for sport athletes who present a narrow vs. wide infrasternal angle (ISA) predisposition.
- Deciding if it is appropriate to feed a speed athlete more compression or expansion strategies.
- How to navigate using heavy strength training to increase compression potential without limiting movement capabilities.
- Training sprinters in the weight room to ensure a proliferation of IR to maximize max propulsion.
- The benefit vs. potential hindrances of table tests.
- Why the “stack” proves necessary for all athletes and gym-goers alike to master.
Wide vs. Narrow Infrasternal Angles
In recent decades, due to the contributions of Hartman, Cupples, Ryan Maron, and a handful of others, coaches can better predict their athletes’ tendencies, compensatory strategies, and developmental needs based on their axial skeleton archetype. An axial skeleton archetype describes the shape of the individual’s spine, thorax, and pelvis. The two broad categories each of us fall into are a wide infrasternal angle and a narrow infrasternal angle.
A majority of Cupples’ recent clientele have consisted of rotational athletes, particularly golfers, for which he describes those who present as a wider frame having a structural build more conducive to force production, which can be identified during their golf swing, as they often turn more horizontally. By contrast, he explained, narrower-framed individuals are built more for rotation and flexibility, leading to a more vertical turn and swing.
“You could look at the ISA as a measure of how someone is built,” Cupples said. “Based on this, there are certain things that structure is more adept at doing than other things. From here, you can then make predictions about how one should present based on the body structure.”
In short, a wide ISA (usually wider than 90 degrees) is characteristic of an individual who has an exhaled, or compressive, biased axial skeleton. The wider anterior rib cage is how their body produces inhalation. Contrarily, a narrow ISA (usually less than 90 degrees) has a more inhaled, expanded/eccentric axial skeleton. The narrow anterior rib cage is how their body exhales.
As a coach, by identifying which ISA (a bony structure we are incapable of changing) our athlete best identifies with, we can better predict how their compensatory breathing strategies might influence their movement capabilities and the natural orientation of their axial skeleton. As a result, we will be in a better position to know which exercises to program and interventions to use to impact the athlete’s overall movement as necessary.
By identifying which ISA our athlete best identifies with, we can better predict how their compensatory breathing strategies might influence their movement capabilities. Share on XFor example, a wide ISA will generally bias in the following ways: “belly breather” with a diaphragm that is descended anteriorly and has difficulty expanding the posterior axial skeleton. From a more movement-based perspective, a wide ISA has a heavy internal rotation and force production bias. This is due to skeletal structure and a pelvis biased toward a state of sacral nutation, allowing for a greater amount of space to move horizontally.
With this, those having a wide ISA will often reveal themselves to be more proficient in movements that require tremendous IR. Exercise and movement examples where a wide ISA will likely be more proficient include:
- Deadlift (KG, BB, trap bar)
- DB and BB press
- Box squat
- Hip-dominant back squat
- Hip-dominant step-up
- RFESS
- RDL (BB, DB, and SL)
Conversely, one of the main reasons athletes with a wide ISA struggle to move vertically (such as during a squat) is because their ability to counter-nutate the sacrum will be limited, making it challenging to create external rotation, or ER (think the initial descent of a squat). However, this does not mean we cannot provide them with vertical squat movements and ER-dominant exercises to enhance their athletic capabilities. Examples to restore and/or promote verticality and ER in a wide ISA would include:
- Heels-elevated DB Zercher squat, goblet squat, and front squat
- Heels-elevated split squat
- Knee-dominant step-up
- Goblet lateral lunge
- Landmine press variations
- Alternating incline press
On the other hand, a narrow ISA will bias toward external rotation, force absorption, and vertical hip displacement and present with a more counternutation sacrum. Exercise and movement examples where a narrow ISA will likely demonstrate greater proficiency due to the ER requirements of these movements include:
- Vertical-biased squatting variations (goblet, SSB, front, overhead)
- Rotation capabilities
- Quad-dominant spit squat (vertical torso split squat)
- Landmine press
Meanwhile, if we want to gradually program exercises to drive IR and compression in an otherwise ER- and expansion-dominant individual, we could implement the following:
- Box squat
- SSB squat
- Bilateral hinge progression-DB RDL to KB deadlift to trap bar deadlift
- Floor press to DB press
- Kickstand RDL to SL RDL
Keep in mind, as Cupples has reminded me on numerous occasions, identifying a client’s ISA angle is an invaluable data point to aid in programming guidelines, but do not misidentify it as the be-all and end-all. (He has an elaborate and excellent encyclopedia on the varying ISA biases that can be found here.)
Creating Space
During recent mentorship calls, Cupples and I focused mainly on the idea of compression versus expansion strategies and identifying the athlete’s needs based on their limitations and sport of choice: an easy-to-digest example would be a powerlifter versus a contortionist.
As one might expect, a powerlifter needs to be able to compress (increase internal pressure) to move heavy weight from point A to point B, making them a prime candidate for compression-biased coaching strategies. However, as Cupples has articulated, a steady diet of too many compression-based movements (let’s use pressing as the example) can reduce overall motion. This may contribute to pain.
As such, a coach needs to identify how to promote compression to aid sporting movement while also using expansion-based strategies to ensure long-term health.
Keeping this in mind, we can flip the script and see how a contortionist would benefit from an elaborate exercise library of expansion movements to reaffirm their ability to maneuver in and out of various positions. This is because a contortionist primarily relies on their ability to create space (availability of movement options). While compression exercises should not be eliminated from a contortionist’s program, as a prerequisite amount of strength is vital to ensure prolonged stability, we can see that too much compression would reduce space and shrink movement choices.
Regardless of what sport the athlete competes in, it is essential to identify if the sport requires a demand bias toward compression, expansion, or a combination of both. Share on XRegardless of what sport the athlete competes in, it is essential to identify if the sport requires a demand bias toward compression, expansion, or a combination of both (tennis, baseball, golf). A sprinter is an interesting case study due to the compression (propel force into the ground) and expansion (short ground contact) demands of the movement.
“If a sprinter works mostly in the sagittal plane, I try to increase available movement by working on rotations and the other motions they may lack,” Cupples told me, explaining that his responsibility as a coach is first and foremost to keep the athlete healthy, and that would entail, believe it or not, providing contrasting movements to sprint training.
By balancing out the amount of compression a sprinter produces on the track with expansion exercises in the weight room, a coach can restore adequate movement—which ideally would result in less pain and fewer injuries. Once that goal has been accomplished, Cupples believes the next step is choosing strategies and movements alternative to the sprint itself, where the athlete can effectively produce force. A handful of advantageous movements to drive posterior expansion for all athletes are as follows:
- Wall sit
- Bench posterior
- Seated posterior expansion with external rotation
- Wall posterior expansion with external rotation
- Dorsal rostral thoracic expansion with posterior hip stretch
- Low reaching sit
Video 1. Wall posterior expansion with external rotation. This will drive posterior expansion and shoulder external rotation and loosen up the upper back muscles.
Video 2. Wall sit posterior expansion. This will drive posterior expansion, shoulder external rotation, and hip internal rotation.
Along similar lines, there remains a constant trade-off when it comes to weight training for field sport athletes. We can conceptualize it as follows: If I am committed to increasing my strength in the weight room, I need to learn how to raise my force production. Additionally, if I desire to raise my force production, I must create more pressure. To create more pressure, I need to reduce the number of options available.
Consequently—and here comes the trade-off—if I limit relative motion, the availability of movement options will decrease, and my potential to move effectively (rotate, shuffle, run forward and backward) will likely spoil. This proves to be quite the dilemma. As Cupples believes, the key with all training qualities is giving the person in front of you “enough.” Analogous to a diet, athletes are not required to consume whole foods 100% of the time to see results—there are elite performers who devour “dessert” every day.
“The way to determine what is enough is by measuring,” Cupples explains. “Ideally, you are looking at a cluster of performance indicators (joint motion, force testing, field performance, etc.) and then determining what the bottlenecks are that are limiting performance. From there, it’s a matter of addressing those bottlenecks until the next one rears its head. Test and retest.”
One of the performance indicators mentioned above is joint motion, which table tests have proven to be adequate in measuring. Table tests prove valuable because they provide a constrained way of examining an athlete’s movement capabilities.
“It’s hard to constrain dynamic movements as much,” Cupples says. “But when working with athletic populations, you’ll need to measure more variables than just range of motion, as there are more needs besides that. But what is nice is if you see table tests trend negatively over the course of a season, it can possibly be a canary in the coal mine for an issue.”
If you see table tests trend negatively over the course of a season, it can possibly be a canary in the coal mine for an issue, says @ZCupples. Share on XOne of the themes Cupples echoes constantly is that coaching is not linear or logical, nor does it always make sense on paper—as coaches, we need to adapt to each athlete’s needs, and the more tools in our toolbox, the more proficient we become at doing this.
Internal Rotation for Sprinting and the Stack
As we returned to the topic of sprinting, I sought to inquire about IR and its relationship to ground contact time and max propulsion. As Hartman once explained, a sprinter lands on their foot near, or right before, max propulsion, which in turn equates to the maximum amount of internal rotation (downward force) being propelled into the ground. Due to the stipulation that we need IR to produce force, it is not uncommon to observe sprinters presenting an anterior-oriented pelvis while leaning their chest and head forward in unison.
Having said that, a sprinter’s ground contact time needs to be purposely succinct to eliminate the elongation of the foot remaining on the ground (which would reduce speed). This then begs the question I posed to Cupples: What various dynamics can we use in the weight room to train our body to produce high levels of IR while reinforcing the need to be quick off the ground?
This first entails working on activities that encourage this rapid transition of force from the foot to the floor and back up again. This could be done by performing repeated jumps, band-assisted hop and stick, continuous hurdle jumps, and for advanced athletes, RRLL. Remember, we want to emphasize to the athlete not to “stick” the landing. Sprinting itself is still the best teacher, but these rapid weight room activities should not be neglected.
As we neared the end of our discussion, I gravitated away from speed-specific modalities and sought Cupples’ opinion on all things the “stack.” For those who are unaware, aside from Cupples’ classic wit, an extensive collection of brim hats, and loyal sidekick Ted, he is probably best known for his mantra, “If you can’t stack, you can’t talk to Zac.” One of the most underrated tools to improve performance, the stack is a movement strategy that involves stacking the thoracic diaphragm on top of the pelvis.
One of the most underrated tools to improve performance, the stack is a movement strategy that involves stacking the thoracic diaphragm on top of the pelvis. Share on X“The stack is foundational for improving movement options,” Cupples said. “It allows for ‘normalizing’ the respiratory mechanism, giving you the potential to have all of your movement options available.”
This would allow for the greatest opportunity to maximize intraabdominal and intrathoracic pressure during movement. During the stack, when we take a breath of air, we should ideally see a multidirectional expansion in the rib cage.
This multidirectional expansion due to proper stacking should enhance relative motion among the ribs, allowing the ribs to separate to make room for an increased amount of air in the lungs while providing greater movement option potential. Keep in mind that the stack is not a posture we MUST hold; it is quite the opposite.
“It’s a movement strategy used to allow for multidirectional movement throughout the body,” Cupples said. “The end result is the appearance of a stacked body. There are several cues focused on (eyes, ground contact, breath, etc.) that can be applied in ALL movements.”
In pointing to sports as an example, he continued, “You need to look at where the play is happening. That’s using the eyes. When you cut, you must push off the foot a certain way to maximize the change of direction. You are ALWAYS breathing. The stack provides consistency within cueing and focus points, making a coach’s job easier over the long haul. The ribcage should expand in all directions during the stack, not migrate forward as a unit.”
For those unaware of how to go about coaching the stack, here is your best resource.
As I began this piece by sharing, it has always been my impression that the hallmark of a good coach, teacher, and educator lies in their ability to restructure otherwise rigorous topics and present them in a digestible form for their athletes and students to comprehend. I have found Cupples stellar in this regard, thanks to his use of numerous visual aids, multiple outside references, constant words of encouragement, impressive level of patience, and genuine sincerity. Just make sure you first learn how to stack, or you can’t talk to Zac.
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