The Exercises You Know, The Intent You Don't
Dr. Stuart McGill's "Big Three" exercises are famous in the fitness and rehab world as a go-to solution for building a resilient, pain-free back. Thousands of people perform the Curl-up, Side Plank, and Bird Dog daily. But if they're so effective, why do so many people still struggle with pain or fail to see real results?
The answer lies in a simple but profound distinction. According to McGill certified practitioner Sam Brown, the most critical factor isn't the movement itself, but the intent behind it. Most people go through the motions without understanding the true purpose of each exercise. This post will reveal the surprising truths behind the Big Three, reframing them as neurological drills designed to train your brain to create stability, not just exercises to strengthen muscles.
The Goal Isn't Movement, It's "Stiffness."
This concept is counterintuitive to most workout philosophies. The goal of the Big Three is not to achieve a certain number of reps or feel a "burn." Instead, the objective is to teach the musculature surrounding your spine how to co-contract and create a rigid, stable core.
This stiffness is what builds a better, more protective brace. It’s this stability that protects your spine from injury-inducing micro-movements during heavy lifts or everyday activities. The focus is on the quality of the contraction and the precision of the position.
To achieve this, the application must also be precise. Dr. McGill often programs these in a reverse pyramid (e.g., five sets, then three, then one), with each hold lasting 10 seconds. The goal is to prime the nervous system for stability, rather than exhausting the muscles.
"...intent is the biggest differentiating factor when you're doing these exercises, whether you are brand new to these exercises or you are an avid lifter that has seen them for years..."
The "Curl-Up" is an Alignment Drill, Not a Crunch
The common mistake is treating the McGill Curl-up like a traditional abdominal crunch, lifting the head and shoulders too high off the floor. The true intent of the exercise has nothing to do with building bulging abs. It is a drill designed to prime the anterior core by teaching you how to align your rib cage and pelvis into a locked, neutral position.
To perform it correctly, lie on your back with one leg extended straight and the other bent. Place your hands under the small of your back to maintain a neutral curve; this provides feedback and a small buffer. Lift your elbows off the floor to hold tension in your core. Before lifting, focus on aligning the rib cage and pelvis. First, tilt your rib cage down. You'll feel your abs and obliques tighten. Then, squeeze your tailbone underneath to bring the pelvis into neutral. Your lower back should flatten towards the floor. Imagine a string pulling your chest straight up to the ceiling. This prevents the common mistake of crunching forward. Finally, use the mental cue to "imagine your head is on a scale, and you want it to just read zero." Lift your head just barely off the floor—no higher—and hold this position with maximum tension for 10 seconds.
The Side Plank Is The Second Hip Hindge
The most surprising truth is that the Side Plank, when done correctly, is a tool for teaching a proper hip hinge in a safe, stable position. Many people hoist their body up and hang passively on their shoulder joint, feeling little more than strain. The intent-driven version is entirely different. It's an active exercise that engages the lats, pecs, obliques, and glutes as a unified system.
Follow this setup to turn the side plank into a powerful teaching tool:
- Start on your side, knees bent.
- First, create upper body tension: Actively drive your elbow into the ground, even imagining you are pulling it towards you, to engage the lats, serratus, and pecs. The source emphasizes you should feel a "pump" in these muscles if done right.
- Next, engage the core: Bring your oblique up, feeling the connection between your engaged lat and your side.
- Finally, perform the hinge: Push your hips forward to fire the glutes, then hinge back. The movement originates from the hips, while the torso remains a rigid, stable plank.
This hinge-up method is deliberately taught because, as the source explains, for someone with a severe disc issue, simply hoisting the hips straight up can be intensely painful. The hinge provides a safer path into the stable position.
"...this is like a sneaky way to get hinging into your day if your lower back hurts..."
For individuals with back pain, a common fear is bending forward. The source refers to this as a "massive mental component." This exercise breaks that mental cycle by providing a safe and stable context to relearn the hinge pattern, teaching the body to fire the glutes and core together without fear.
The Bird Dog is a Full-Body Press
The most common error with the Bird Dog is passively "throwing" an arm forward and "kicking" a leg back with no tension or stability. The true intent of the Bird Dog is to be a full-body stability movement that challenges your ability to prevent rotation. Think of the setup cues you would use for a heavy bench press.
A correct Bird Dog feels like a press against an immovable object:
- Start on all fours with your hands directly under your shoulders. Create force by pushing your hands into the ground, making your upper back stable and tall.
- Use the same mental cue as a bench press: pull your shoulder blades down into your back pockets to engage your lats and create a stable shelf for the movement.
- Lock your core by keeping your rib cage and pelvis in a neutral alignment.
- Extend one arm straight forward as if you are trying to "punch a hole in the wall in front of you."
- Simultaneously, drive the opposite heel straight back. You are not lifting the leg high; you are extending the hip and driving the heel away from you.
- The goal is to perform this extension with zero movement in your torso. Your body should remain perfectly still and rigid.
For beginners, it's often more effective to practice moving just one limb at a time. This helps develop the necessary neurological control to maintain stability before progressing to moving an opposite arm and leg together.
Train Your Brain, Not Just Your Body
The actual value of the McGill Big Three is unlocked through precise, focused intent, not mindless repetition. They are neurological drills designed to enhance your brain's ability to stabilize your spine.
Each exercise is designed to enhance your brace's effectiveness by challenging your core to maintain a neutral spine from various directions. By focusing on alignment, tension, and stiffness, you are training a skill that has a direct carryover to every lift you perform and every daily task you undertake.
