Evolution of Our Chassis Integrity Theory

Train Chassis Integrity: 25 Minutes, 1x Sandbag, 3x Exercises

By Rob Shaul, Founder

Our Chassis Integrity programming theory evolved after a personal experience in 2015. I had moved away from the tactical programming to some distance running and bodyweight work. The bodyweight training included plenty of core work – sit-up variations, bridging, lower back complexes, EO’s, and some ground and equipment based work such as Russian Triangles, Ankles to Bar, GHD Sit ups, etc.

Further, my core circuits pushed beyond what I commonly programmed for athletes in both: rounds and duration. I really hammered it – or so I thought.

After a couple of months, I got back underneath the barbell for some front squats and struggled to go heavy. My legs were strong, in isolation, and my core was strong, in isolation, but the link and coordination between the two weren’t there – I lacked “chassis integrity.”

This had a real impact on me – as I’d hammered my midsection, but all that work hadn’t translated into the functional task of lifting heavy while standing. It caused me to question my core programming theory to that point and I began to develop the Chassis Integrity model.


Before Chassis Integrity

Our prior core training theory had alternated between two circuits – FIRE, and LBC.

“FIRE” is an acronym for “Flexion / Isometric / Rotational / Extension”. A FIRE Circuit has one exercise from each, for example:

4 Rounds

  • 10x Weighted Sit up @ 25# (Flexion)
  • 30/30 Side Bridge (Isometric)
  • 10x EO’s (Rotation)
  • 10x GHD Back Extension (Extension)

“LBC” is an acronym for “Low Back Complex” and we learned this approached from the book “Foundation Training,” by Eric Goodman and Peter Park. The authors note that few miss a day of work because of ab pain, and correspondingly wondered why so much core training focused on the front of the body, and not the low back. They aimed to change this, and our typical Low Back Complex circuit comes from their exercise menu. Below is an example. I’ve since expanded the scope of our Low Back Complex to mean a circuit of four extension exercises.

4 Rounds

  • 20/20 Standing Founder
  • 20/20 Low Back Lunge
  • 20/20 Kneeling Founder
  • 10x Face Down Back Extensions


Chassis Integrity Theory

My experience in 2015 caused me to question three things about this core training approach.

First, why were we doing so many ground or equipment based core exercises when in reality most core work is done standing? I reasoned that not performing core exercises from a standing or kneeling position had compromised my chassis integrity.

Second, I questioned the need for isometric and flexion core exercises in general. Real life core for the athletes we serve (mountain/tactical) is seems dominated by extension and rotational movement patterns. Real life also includes isometric work, but not in the way we had been training it. More specifically, rather than isometric work, what really occurs is anti-rotation. Mountain and Tactical athletes must fight force trying to torque them rotationally.

Third, previously I had programmed core circuits using the standard round and reps format used as examples above. This approach seems to train strength, but not necessarily strength endurance. Perhaps grinds for time would be more transferable outside the gym, I reasoned.

What evolved is a new approach to core training – Chassis Integrity.

First, I moved away from most ground-based core exercises to prescribing exercises performed either standing or kneeling. To achieve Chassis Integrity I needed to train the system holistically.

Second, I began to replace the FIRE circuits in favor of Chassis Integrity circuits and move from rounds and reps, to time. Theory on these is still fluid as our testing continues, but as of now, we deploy 3 types of Chassis Integrity Circuits, each with 3x exercises.


Chassis Integrity Circuit 1 includes one each of a total body, rotational and anti-rotational core exercise. Here’s an example:

20-30 Minute Grind


Chassis Integrity Circuit 2 includes Two total body core exercises and one rotational exercise. One of my favorite circuits of this style can be completed with one sandbag:

20 Minute Grind

See the clip above to watch me grind through one of these circuits last Thursday.

Chassis Integrity Circuit 3 again combines exercises from three movements, except that one of the movements is an extension (low back) exercise. Example:

20 Minute Grind

One element that the Chassis Integrity circuits bring which was missing from the FIRE circuits and a serious work capacity component. While I never quite reach panic breathing during these circuits, the total body component has certainly gotten me close.


Common Questions

Why is Chassis Integrity more appropriate for Mountain and Tactical Athletes?
Foremost is its transferability outside the gym to the real world. The Chassis Integrity movements and exercises closely mirror the midsection strength and strength endurance demands faced by mountain and tactical athletes. Most likely, these athletes will be lifting or moving something fairly heavy, bulky and awkward and deploying extension, rotation and isometric strength (total core) in one movement.

As well, sometimes real world midsection strength demands a single movement. But more often, mid-section strength is a strength endurance effort – think uphill hiking with a heavy pack for miles. Chassis Integrity, with it’s extended “grind” duration, trains not only the absolute midsection strength for single events but also the strength endurance needed for extended work.

Have you and your athletes noticed a difference?
Absolutely – anecdotally, myself, I’ve seen a significant improvement in real-world midsection strength for activities like hauling out game from a backcountry hunt or getting firewood. Several of my athletes, both mountain and tactical, have reported similar improvement and experience. It’s like we’ve built and integrated band of muscle and functionality around our midsection.

Questions, Comments, Feedback? Email coach@mtntactical.com



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