When someone tells you to “strengthen your core” or “engage your core,” what does that actually mean?
Most people immediately think of their abs.
But your core is much more than a six-pack.
Your core is a group of muscles around your trunk and pelvis that work together to support your spine, control movement and transfer force between your upper and lower body.
You use these muscles when you walk, run, lift something off the floor, carry groceries, play sports, climb stairs and even breathe.
And while core strength can be an important part of preventing and rehabilitating certain injuries, having back pain does not automatically mean you have a “weak core.”
At Restorative Touch Physiotherapy on Hamilton Mountain, we often assess core strength, endurance and trunk control as part of a much larger picture that includes mobility, strength, workload, previous injuries, activity level and the specific movements that are causing symptoms.
So what exactly is your core—and why does it matter?
What Is the Core?
The simplest definition is:
Your core is the muscular system surrounding your trunk and pelvis that helps control and stabilize your body during movement.
Think of it as a muscular cylinder around your midsection.
It includes muscles at the:
- Front of your abdomen
- Sides of your abdomen
- Back of your trunk
- Pelvis
- Base of the pelvic floor
- Top of the abdominal cavity through the diaphragm
Several muscles around the hips and pelvis also work closely with your core during movement.
Your core’s job isn’t simply to make your stomach look muscular.
It helps your body:
- Control movement of the spine and pelvis
- Transfer force between your arms and legs
- Maintain positions under load
- Resist unwanted rotation or bending
- Lift and carry objects
- Run, jump and change direction
- Perform everyday activities efficiently
That’s why core training involves much more than crunches and sit-ups.
What Muscles Make Up Your Core?
There isn’t one universally agreed-upon list of “core muscles.”
Instead, many muscles work together depending on what you’re doing.
Important muscles include:
Rectus Abdominis
This is the muscle most people associate with the “six-pack.”
It helps flex the trunk and also contributes to controlling your torso during movement.
Internal and External Obliques
Your obliques are located along the sides of your abdomen.
They help with:
- Rotation
- Side bending
- Trunk control
- Stabilization during movement
They become particularly important during activities involving twisting, throwing, running and changing direction.
Transversus Abdominis
The transversus abdominis, or TrA, is one of the deepest abdominal muscles.
It wraps around your abdomen somewhat like a corset.
Rather than producing large visible movements, it contributes to abdominal pressure and trunk control when you move or lift.
Multifidus
The multifidus consists of small muscles running along the spine.
These muscles contribute to controlling movement between individual segments of the spine and maintaining spinal stability.
Erector Spinae
The erector spinae are larger muscles running along your back.
They help extend and control movement of the spine and play an important role when lifting, bending, standing and carrying.
Diaphragm
Yes—your primary breathing muscle is also part of the system involved in trunk stability.
Your diaphragm works with the abdominal muscles and pelvic floor to help regulate pressure inside your abdominal cavity.
This is one reason breathing and core control are closely connected.
Pelvic Floor
The pelvic floor forms the bottom of this muscular system.
It contributes to:
- Bladder and bowel control
- Pelvic organ support
- Pressure management
- Trunk stability
- Sexual function
The pelvic floor doesn’t simply need to be “strong.”
Like other muscles, it needs to be able to contract, relax and coordinate appropriately.
People experiencing pelvic-floor symptoms may benefit from an assessment with a pelvic health physiotherapist.
Glutes, Hips and Other Muscles
Your gluteal muscles, quadratus lumborum, latissimus dorsi and muscles around the hips can also contribute significantly to trunk and pelvic control.
The important takeaway is:
Your core isn’t one muscle. It’s a coordinated system.
What Are the “Inner” and “Outer” Core Muscles?
You may hear physiotherapists, trainers and rehabilitation professionals describe the core as having an inner unit and outer unit.
This can be a useful way of explaining how different muscles contribute to stability, although your body doesn’t literally divide your muscles into two independent systems.
The deeper or “inner” muscles commonly discussed include:
- Transversus abdominis
- Multifidus
- Diaphragm
- Pelvic floor
The larger or more superficial muscles may include:
- Rectus abdominis
- Internal and external obliques
- Erector spinae
- Quadratus lumborum
- Latissimus dorsi
- Gluteal muscles
In reality, these muscles work together.
Your nervous system constantly adjusts how much each muscle contributes depending on the task.
Picking up a coffee mug requires very little trunk stiffness.
Deadlifting a heavy barbell requires considerably more.
Your core should be able to produce the right amount of tension for the activity you’re performing.
What Does Your Core Actually Do?
One of the biggest misconceptions about the core is that its job is simply to move your spine.
Often, its job is actually the opposite.
Your core frequently works to resist movement.
Imagine carrying a heavy grocery bag in one hand.
Gravity tries to pull your trunk toward that side.
Your core muscles automatically generate force to keep you upright.
The same thing happens during:
- Running
- Lifting
- Pushing
- Pulling
- Throwing
- Carrying
- Squatting
- Changing direction
This is why effective core training often includes exercises that challenge your body to resist:
Extension — such as a dead bug.
Rotation — such as a Pallof press.
Side bending — such as a side plank or loaded carry.
Excessive trunk movement under load — such as properly progressed squats, hinges and carries.
Eventually, good core training should transfer into the activities you actually want to perform.
Does a Weak Core Cause Lower Back Pain?
This question deserves a more nuanced answer.
Sometimes core strength, endurance or coordination may contribute to lower-back symptoms—but back pain is rarely caused by one weak muscle.
Research has found differences in trunk muscle function in some people experiencing low-back pain.
However, that does not mean the abdominal muscles simply “switch off.”
Lower-back pain is influenced by many possible factors, including:
- Activity level
- Strength and physical capacity
- Sudden changes in workload
- Previous injuries
- Sleep
- Stress
- Repetitive activity
- Mobility
- Recovery
- General conditioning
- Individual anatomy
- Sensitivity of the nervous system
Two people can have similar core strength and completely different experiences with back pain.
That is why simply telling every person with back pain to “strengthen your core” is usually an incomplete approach.
Can Core Exercises Help Lower Back Pain?
They can.
Research supports core stabilization and exercise-based rehabilitation as useful options for many people with nonspecific lower-back pain.
But core exercises aren’t magic.
A good rehabilitation program may also involve:
- General strengthening
- Hip and leg strengthening
- Mobility exercises
- Gradually increasing physical activity
- Education about pain
- Modifying aggravating activities temporarily
- Improving lifting or movement tolerance
- Building endurance
- Returning progressively to work, sport or exercise
The best exercise program depends on the individual.
Someone whose back hurts after sitting at work all day may need a very different program from someone whose back hurts when deadlifting or playing soccer.
If you’re experiencing recurring lower-back pain, our Physiotherapy Services can help identify which factors may actually be contributing to your symptoms.
Is the Transversus Abdominis the Most Important Core Muscle?
The transversus abdominis receives a lot of attention in rehabilitation.
And it is important.
But it isn’t a magic muscle.
Your spine doesn’t rely on one abdominal muscle to keep it safe.
Effective trunk control comes from multiple muscles working together at the right time and at the right intensity.
Trying to consciously contract your transversus abdominis all day isn’t necessary.
Neither is constantly sucking your stomach in.
For a more detailed explanation of how your abdominal muscles should actually feel when you brace, read our guide:
How to Tighten Your Core Properly: An Evidence-Based Guide.
Should You Suck Your Stomach In to Activate Your Core?
Usually, no.
There is an important difference between:
Sucking in: pulling your stomach inward as much as possible.
and
Bracing: creating controlled tension around your trunk while continuing to breathe.
Imagine someone is about to gently push you in the stomach.
You would naturally firm your abdominal muscles without necessarily sucking your stomach inward.
That is closer to abdominal bracing.
Importantly, the amount of tension you need should change depending on the task.
Walking around your house doesn’t require the same level of core stiffness as lifting something heavy.
How Do You Strengthen Your Core?
A strong core should be able to handle different forces, positions and movements.
That means your program shouldn’t consist exclusively of crunches.
Depending on your ability and goals, useful core exercises may include:
- Dead bugs
- Bird dogs
- Side planks
- Front planks
- Pallof presses
- Glute bridges
- Loaded carries
- Cable rotations
- Squats
- Lunges
- Deadlift or hip-hinge variations
The right exercise depends on your current ability.
For someone recovering from pain, lying on the floor performing a dead bug may be challenging enough.
For an athlete, that same exercise may eventually become far too easy to create a meaningful training stimulus.
Core exercises should progress as your body gets stronger.
How Do You Know If Your Core Is Weak?
There isn’t one simple test that definitively determines whether you have a “weak core.”
A physiotherapy assessment may look at several things, including:
- Trunk strength
- Muscular endurance
- Balance
- Hip strength
- Coordination
- Movement control
- Breathing patterns
- Tolerance to lifting
- Sport-specific movement
- Work-related tasks
More importantly, we want to know:
What are you having difficulty doing?
Someone may perform a two-minute plank but still struggle to control their trunk during a high-speed change of direction.
Another person may have excellent gym strength but limited endurance for an eight-hour physical workday.
Strength should always be considered in the context of what your body needs to do.
Do Planks Strengthen Your Core?
Yes.
Planks can be a useful core exercise because they require your trunk muscles to resist movement.
But they aren’t the only core exercise—and eventually they may not be challenging enough.
You can progress core training by changing:
- Resistance
- Lever length
- Duration
- Position
- Speed
- External load
- Arm or leg movement
- Balance demands
The goal isn’t to become exceptionally good at planking.
The goal is to improve your body’s ability to handle the demands of your everyday life, job, exercise or sport.
Do You Need to Keep Your Core Tight All Day?
No.
Your body is designed to move.
You do not need to walk around consciously bracing your abdominal muscles throughout the entire day.
Your nervous system normally adjusts trunk muscle activity automatically.
Core training is about improving your body’s capacity to produce appropriate stability when it is needed, not maintaining maximum abdominal tension 24/7.
Core Strength and Back Pain: The Bottom Line
Your core is much more than your abdominal muscles.
It is a coordinated system involving muscles around your abdomen, spine, pelvis and hips that helps you:
- Move efficiently
- Transfer force
- Lift and carry
- Control your spine and pelvis
- Participate in exercise and sport
- Handle the physical demands of everyday life
And although core exercise can be useful for people experiencing lower-back pain, back pain does not automatically mean you have a weak core.
Effective rehabilitation should look at the whole person.
At Restorative Touch Physiotherapy on Hamilton Mountain, our physiotherapists assess your strength, mobility, movement, physical capacity and goals before developing an individualized rehabilitation program.
If you’re struggling with recurring lower-back pain, weakness or difficulty returning to exercise, explore our Physiotherapy Services or Book a Physiotherapy Assessment in Hamilton to find out what your body actually needs.
Frequently Asked Questions About Core Strength
What muscles are considered your core?
Your core includes several muscles around your abdomen, back and pelvis, including the rectus abdominis, obliques, transversus abdominis, multifidus, erector spinae, diaphragm and pelvic floor. Muscles around your hips and pelvis also contribute during many activities.
Is your core just your abs?
No. Your abdominal muscles are only one part of your core. Your back muscles, pelvic floor, diaphragm and several muscles surrounding your pelvis also contribute to trunk stability and movement.
Can a weak core cause back pain?
Reduced trunk strength or endurance may contribute to symptoms in some people, but lower-back pain is multifactorial. Having back pain does not automatically mean your core is weak.
Will strengthening my core get rid of lower-back pain?
Core strengthening can be helpful for some people with lower-back pain, but it is usually only one component of rehabilitation. Your program may also involve mobility, general strengthening, activity modification and progressively rebuilding tolerance to the activities that cause symptoms.
What is the best core exercise?
There isn’t one best exercise for everyone. The right exercise depends on your current strength, symptoms and goals. Dead bugs, bird dogs, side planks, Pallof presses and loaded carries are examples that can be progressed as your ability improves.
How often should I train my core?
That depends on the intensity of the exercises, your current fitness level and the rest of your training program. Your core already works during many compound exercises and everyday activities, so more isn’t necessarily better.
Should I tighten my core when lifting?
Creating appropriate trunk tension can help when lifting heavier loads. The amount of bracing required should match the demands of the lift rather than contracting your abdominal muscles as hard as possible for every movement.
Core Strengthening & Physiotherapy in Hamilton
If you’re experiencing persistent lower-back pain, having difficulty exercising or aren’t sure whether you’re performing core exercises correctly, an individualized assessment can help.
At Restorative Touch Physiotherapy on Hamilton Mountain, we combine education, progressive exercise, hands-on care when appropriate and individualized rehabilitation to help you build the strength and capacity required for the activities that matter to you.
Instead of simply telling you that your “core is weak,” we want to determine what your body actually needs.
Learn more about our Physiotherapy Services, read How to Tighten Your Core Properly, or Book an Appointment with our Hamilton physiotherapy team.
Here are some exercises of outer and inner core strengthening:
