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The Limiting Factor Theory (Complete with Photos of Minions, Channing Tatum, and A Puppy)

Poor duck.

How about that weather yesterday? It was almost warm enough for shorts!

In other news, how about that championship game last night? In case anyone was wondering, I heard somewhere that, had the BCS still been intact, Florida State and Alabama would most likely have been selected to play in the BCS Championship. So I guess that means Ohio State is the Ravens from 2012 and Alabama is the Broncos from this year, right?

One thing that really guides my thoughts on training is this new thing that I call The Limiting Factor Theory.

It’s not anything new. It won’t put 10 lbs of muscle onto your traps in six weeks and isn’t going to tone that fat on your arms that shakes every time you extend your arm out and shake it back and forth. The Limiting Factor Theory is simply the explanation behind almost all of the training decisions that great coaches have ever made. It works for powerlifters, bodybuilders, Oly lifters, and 21 year old dudes that want to be ripped, but not too big, you know, kind of like Channing Tatum, but only a little skinnier. And more ripped.

I want to look less like the guy on the left and more like the guy on the right.

Will This Work For Athletes?

Mike Boyle is famous for saying (and I’m paraphrasing here), “The squat is not a leg exercise, it’s a lower back exercise.” As part of the argument, Boyle has mentioned things like extending the spine and flexing the spine and how adding all of this to a large compressive force on the back is a recipe for disaster. He doesn’t program back squats for his athletes anymore because what his athletes need is leg strength, not necessarily back squat strength. And of course, internet weightlifting minions everywhere became outraged at this statement.

Ah, those internet minions again.

I would be willing to program back squats for somebody if it were the right choice given their goals. However, a few notes first. Extension and flexion of the spine is bad, but it is entirely possible to squat with a neutral spine the entire time. And although heavy weight on the back makes for a high compressive force, sheer forces are what really seem to cause us problems. (Think of compressive forces as parallel to the spine, whereas sheer forces are perpendicular.)

But back to what Mike Boyle said: the back squat is a lower back exercise. It is, according to the Limiting Factor Theory. Since the weakest link in the back squat is the lumbar erectors, we can only squat what our lower back can withstand. Therefore, our lumbar erectors are the only muscle group truly working at their max.

For this reason, Boyle uses single-leg exercises to strengthen the legs of his athletes. This makes sense because although it is important to have a strong lower back, athletes sprint faster, jump higher, and hit harder by having stronger legs. Single-leg exercises take the lower back out of the equation and allow for fuller leg development. (This is the same reason that a powerlifter might use a leg press as an accessory movement to his squat. It strengthens the legs without being limited by the lower back.)

Single-leg movements allow us to put a heavy load on each leg without being limited by our back.

What About Body Transformations?

Bret Contreras is known as the glute guy and spends much of his day thinking about people’s butts.

Before anyone knew who Bret Contreras was, though, he was on a magical quest to discover the best exercises for glute development. (For the record, I’m all-in on the glute development thing. From aesthetics to performance to health, there probably isn’t another muscle in the body that can have as big of an influence as the glutes.)

Classically, the squat and deadlift have been the king of developing the legs, including the glutes. But Bret was a true visionary and believed in more than that. So he began experimenting in his secret glute lab to find out which exercises would truly bring about the greatest glute development.

This is my glute lab.

Since we already know that the squat is limited by the lower back, we can remove it as the best exercise for glute development. And if we look at the deadlift, we see the same pattern.

So then we move onto our single-leg stuff, a la Mike Boyle. But a quick look at single-leg work leaves us unimpressed. There is an abundance of muscles working during single-leg movements, including the quads, hamstrings, and glutes. Furthermore, the glutes (along with other muscles) are working hard to stabilize the femur in the frontal and transverse planes. So let’s apply our Limiting Factor Theory.

It depends on the person, but the limiting factor could be any of the above. And just based on experience, it’s probably not the glutes as a hip extensor. My guess is that it will most likely be our quads or femoral stabilizers.

So, unhappy with traditional powerlifts and single-leg movements, Bret moved onto the hip thrust, figuring that distributing the weight directly on the pelvis would place the emphasis on the glutes as hip extensors!

And he was right! To this day, Bret Contreras has used the Limiting Factor Theory and the hip thrust to transform thousands of backsides. If you’re looking to build up a certain part of your body, keep in mind that exercises where that bodypart/muscle group is the limiting factor will provide the best bang for your workout buck!

She might not, she might just do a lot of hip thrusts and external rotations.

And What About Powerlifting?

This might be the most classic example. If you look at anything written by Louie Simmons, Dave Tate, Jim Wendler, or anyone else out of Westside or Elite, it probably includes lots of work for the triceps and back extensors. That’s because these guys know that the powerlifts are traditionally limited by those muscles!

Even in raw powerlifting, the limiting factors in the bench press and squat are almost always the triceps and erectors, respectively.

But this goes beyond just training certain muscles. In powerlifting, lifters will often train certain partial movements to prepare themselves to blow through PRs in the full range-of-motion.

For instance, common movements to assist the bench press are lockouts and floor presses. Not to mention, bands, reverse bands, and chains alter the tension through the range-of-motion so that the weight becomes heavier as you get closer to lockout.

The deadlift and squat are the same story. Bands, reverse bands, chains, rack pulls. These tools are all designed to help lifters break through sticking points. Ever wonder why Westside and Elite prescribe the good morning so much? As they say, “Big good mornings equal big squats.” (Again, I paraphrased that.) This is because the squat and deadlift are traditionally limited by back extensor strength.

Not this good morning, this won’t make you a better squatter.

Of course, you would never neglect the bench press or other movements to strengthen the chest. You also wouldn’t neglect the leg press, single-leg work, or full range-of-motion squats and deadlifts. But powerlifters recognize use the Limiting Factor Theory every workout to get stronger.


Like I said in the beginning, the Limiting Factor Theory is not a new idea, program, or workout. It is simply an explanation for why certain exercises and movements work for certain goals.

If we have aesthetic goals, our job is to find ways to make certain bodyparts or muscle groups the limiting factor of our exercises. For instance, bodybuilders use fly variations to hammer the chest. But they also use the idea of pre-exhausting muscles with isolation exercises before compound movements. Flys before bench, single-leg before squats, you get the idea.

For performance goals, we might use the Limiting Factor Theory to choose our accessory movements (triceps and lower back movements for powerlifters, squat variations for Oly lifters). Or maybe it helps guide us away from movements that don’t quite fit the bill as far as athlete training.

No matter what our goals are, a chain is only as strong as it’s weakest link. If you’re looking to strengthen the chain, strengthen the weakest link first! Or at least pre-exhaust that link so that you can hammer it into oblivion with multiple high-rep sets of squats.

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