How to Do the McGill Big 3: Technique, Progressions and Common Mistakes

The McGill Big 3 — the modified curl-up, side plank and bird dog — train trunk endurance and control while limiting unnecessary movement through the lumbar spine. They look simple, but small technique errors can change what you practise.

This detailed guide builds on our introduction to the McGill Big 3. Use it to refine each position, select an appropriate regression and progress without turning quality work into a fatigue contest.

The main rule: quality before fatigue

The Big 3 are not about chasing the longest hold or the highest repetition count. Your aim is a firm, controlled torso while the hips and shoulders contribute appropriately. End a set when your position changes, your breathing becomes strained or symptoms clearly increase.

You need only a comfortable floor and enough room to move. A mirror, coach or training partner can make position checks easier. If you have acute pain, spreading symptoms, loss of sensation or noticeable weakness, seek assessment from a qualified health professional before starting.

1. Modified curl-up

Step-by-step technique

1. Lie on your back with one leg straight and the other knee bent.
2. Place your hands under the natural curve of your lower back. Do not press the lumbar spine flat into the floor.
3. Gently brace as if preparing for a light push against your abdomen.
4. Lift your head and shoulders only a small distance without changing the shape of your lower back.
5. Hold briefly, continue to breathe and lower with control.

Common mistakes

• Turning the movement into a high sit-up.
• Pulling the chin hard toward the chest.
• Flattening and repeatedly flexing the lower back.
• Holding the breath or bracing at maximum effort.

If the exercise feels too demanding, reduce the range and shorten the hold. A larger movement is not necessarily a better one.

2. Side plank

Step-by-step technique

1. Position your elbow approximately under your shoulder.
2. Start from bent knees if needed, keeping knees, hips and shoulders aligned.
3. Lift the hips without rotating forward or backward.
4. Keep the neck long and actively press away from the supporting shoulder.
5. Breathe calmly, then lower under control.

The bent-knee side plank is a useful regression, not a lesser exercise. Move to straight legs only when you can maintain alignment without a clear increase in symptoms.

Common mistakes

• Letting the hips sag or pushing them excessively high.
• Rolling the upper shoulder forward.
• Hanging passively on the supporting shoulder.
• Progressing before the basic position is repeatable.

3. Bird dog

Step-by-step technique

1. Begin on hands and knees, with hands under shoulders and knees under hips.
2. Create gentle trunk stiffness without holding your breath.
3. Reach one leg behind you and the opposite arm forward.
4. Keep the pelvis quiet and think about becoming long rather than lifting high.
5. Return slowly and repeat on the other side.

Reach through the heel instead of trying to lift the foot toward the ceiling. Excessive height often produces lumbar extension or trunk rotation.

Common mistakes

• Arching the lower back to raise the leg.
• Opening the pelvis toward one side.
• Moving too quickly to control the end position.
• Using more range than you can stabilise.

A sensible starting structure

Begin with the version you can perform consistently. One commonly used structure is a descending set, such as six repetitions, then four, then two on each side. Short, high-quality holds of roughly eight to ten seconds are often more useful than one long, exhausting hold.

That is an example, not a personal prescription. The right volume depends on your current capacity, symptoms, sport and other training. Two to four practice sessions per week may be a reasonable starting range for some people. Review how you feel later that day and the following day before adding more.

How to progress the McGill Big 3

Change one variable at a time:

• add a small number of repetitions;
• add one set;
• use a longer lever, such as a side plank from the feet;
• improve precision while using slightly less rest.

Do not add load simply because the basic movement looks easy. First make the position repeatable, the breathing calm and the transition controlled.

Frequently asked questions

Should I do the McGill Big 3 every day?

Not everyone needs to. Frequent practice can help skill, but recovery and total training load still matter. Use a frequency that preserves technique and does not produce a worsening symptom pattern.

Should the exercises hurt?

Muscular effort is expected. Sharp, spreading or clearly increasing pain is not the objective. Stop, regress the movement and seek professional guidance if you are unsure.

Are the Big 3 a complete back programme?

No. They are a foundation, not a diagnosis or complete rehabilitation plan. Walking, daily movement habits, load management and individual pain triggers may all matter. Back Mechanic explains that broader approach; the video-enhanced edition adds demonstrations.

Key takeaways

A productive Big 3 session should look controlled: a stable lumbar position, calm breathing and final repetitions that resemble the first ones. Select the regression that suits you, progress one factor at a time and place these exercises inside a wider plan.

Next, compare Back Mechanic vs Gift of Injury, or browse all Stuart McGill books.

This article is general information and is not a diagnosis, treatment plan or personal exercise prescription. Seek qualified medical care for severe, new or persistent symptoms.