The Bill Kazmaier Fulcrum Technique for Fully Activating Your Erector Muscles.
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Squat University breaks down a fulcrum board exercise, picked up by Dr. Stuart McGill from strongman Bill Kazmaier, that targets the erector muscles standard lat exercises and even deadlifts miss. Because each spine segment has its own nerve, this technique can push a specific erector compartment toward 100% activation, versus the 60-70% seen from a deadlift or RDL.
Key takeaways
- According to Squat University, standard lat exercises don't activate the smaller erector muscles in the back to 100%.
- Dr. Stuart McGill picked up a fulcrum board technique from strongman Bill Kazmaier to target specific erector compartments.
- Raising the board fulcrum shifts neural drive to the upper neuromuscular compartments of the back; lowering it shifts drive lower.
- A deadlift or RDL activates the erectors at only 60 to 70% of their max ability, according to Squat University.
- Unlike the quads, which are all driven by the single femoral nerve, each spine segment's erectors (like at T7) has its own individual nerve wiring.
- This segment-specific approach can push erector activation to 100%, which is useful before a heavy deadlift or loaded carry.
Why don't lat exercises fully activate the erector muscles?
Big lat-focused exercises build the larger back muscles well, but they leave the smaller erector muscles under-activated. Squat University points out that these deeper muscles, shown in blue in the anatomy graphics from Muscle and Motion, aren't hit at 100% during a typical lat movement. That gap is why a separate, targeted approach is needed for the erectors specifically — which is where the technique below comes in.
How does the Bill Kazmaier fulcrum technique work?
The technique uses boards to create a fulcrum that redirects neural drive to specific segments of the erector muscles along the spine. Dr. Stuart McGill picked up this method from Bill Kazmaier, described as one of the strongest athletes of all time. Here's how it's performed:
- Set up boards to create a fulcrum point.
- Grip hard and contract — with the fulcrum raised, neural drive shifts to the upper neuromuscular compartments on the working side.
- Lower the fulcrum, and neural drive shifts down to the lower neuromuscular compartments.
- Combine positions to link compartments up and down the back, building a dense neural drive useful for a loaded carry or heavy deadlift.
This lets you dial in exactly which segment of the erectors gets the strongest signal, rather than firing the whole muscle group generically.
Why do erector muscles need segment-specific training unlike the quads?
Erector muscles need segment-specific training because, unlike the quads, each spine segment has its own individual nerve. The quads are all innervated by a single nerve — the femoral nerve — so when it fires, all the quad muscles contract together to extend the knee. The erectors don't work that way: the erectors at T7, for example, are innervated by their own dedicated nerve, separate from the segments above and below.
This is why a compound lift can't maximize every erector segment at once. According to Squat University, a deadlift or RDL only activates the erectors to about 60 to 70% of their max abilities, whereas the fulcrum board technique lets you isolate and push a specific segment toward 100% activation when you need it most.
Notable quotes
I want to share with you a novel exercise you've never seen before to optimize the activation of your erector muscles in your back that Dr. Stuart McGill picked up from one of the strongest athletes of all time, Bill Kazmaier.
What I'm doing is creating a little bit of a fulcrum with these boards so that when I grip hard and contract, my brain is going to the neuromuscular compartment high up on my right-hand side.
With the erectors, it's different. Each spine segment has its own individual wiring.
A deadlift or an RDL may focus on the erectors and activate them 60 to 70% of their max abilities, this allows you to really focus on each individual compartment but optimize their activation to 100%.
Frequently asked questions
What is the Bill Kazmaier fulcrum technique for back exercises?
According to Squat University, it's a technique picked up by Dr. Stuart McGill from strongman Bill Kazmaier that uses boards to create a fulcrum during a grip-and-contract movement. Raising the fulcrum shifts neural drive to the upper neuromuscular compartments of the erectors, while lowering it shifts drive to the lower compartments, letting you target the spine segment you need.
Why don't deadlifts fully activate the erector muscles?
Because a deadlift or RDL only activates the erectors to about 60 to 70% of their max ability, according to Squat University. That's because each spine segment's erector fibers, like at T7, are innervated by their own individual nerve rather than one nerve firing the whole muscle group at once, so a compound lift can't max out every segment simultaneously.
How are the erector muscles different from the quad muscles in terms of nerve activation?
The quads are all innervated by a single nerve, the femoral nerve, so they contract together at roughly the same time when extending the knee. The erectors are different: each spine segment, such as T7, has its own individual nerve wiring, which is why Squat University says you need a segment-specific exercise to hit 100% activation rather than relying on a compound lift.
Who created the fulcrum board exercise for the back erectors?
Dr. Stuart McGill picked up the exercise from Bill Kazmaier, described by Squat University as one of the strongest athletes of all time. The move uses boards as a fulcrum during a hard grip-and-contract to direct neural drive up or down the erector muscles along the spine.
What percentage of the erectors do deadlifts and RDLs activate?
Squat University states that a deadlift or RDL activates the erector muscles at roughly 60 to 70% of their maximum ability. The fulcrum board technique from Bill Kazmaier and Dr. Stuart McGill is presented as a way to push individual erector compartments closer to 100% activation instead.
Full transcript
0:00Why standard lat exercises miss the erectors
An exercise like that will really build your bigger lat muscles on your back. But what about these smaller muscles shown in blue? They're not activated 100% during an exercise like that. I want to share with you a novel exercise you've never seen before to optimize the activation of your erector muscles in your back that Dr.
Stuart McGill picked up from one of the strongest athletes of all time, Bill Kazmaier.
0:26Bill Kazmaier's board fulcrum technique demonstrated
What I'm doing is creating a little bit of a fulcrum with these boards So that when I grip hard and contract, my brain is going to the neuromuscular compartment high up on my right-hand side. By lowering the fulcrum a little bit, I've now shifted my brain down to the neuromuscular compartments here. So I'm able to put together these neuromuscular compartments up and down the back to create a very dense neural drive For something like a carry, a loaded carry, or a heavy deadlift.
1:07Why erector muscles activate differently than quads
So this is fundamentally different than other parts of the body. The quads, for example, are all innervated by the femoral nerve. So when it sends power to the quads to extend the knee, all the quad muscles contract relatively at the same time. But with the erectors, it's different.
Each spine segment has its own individual wiring. So all the erectors at T7 are innervated by the exact same nerve, and so on down the spine. So whereas a deadlift or an RDL may focus on the erectors and activate them 60 to 70% of their max abilities, this allows you to really focus on each individual compartment but optimize their activation to 100%. So if you really need to focus on your erectors at a specific segment, this is where you go.
Mentioned in this video
- Dr. Stuart McGill
- Bill Kazmaier
- Dr. Aaron Horschig
- Squat University
- BackFitPro
- Muscle and Motion
- erector spinae
- deadlift
- loaded carry
- RDL