Walk into any gym or health club and you’ll find people exercising their core. Core training has taken the world by storm, and for good reason as strengthening the core creates stability and better movement and helps prevent lower back pain. To help you get the most out of your efforts, it’s important you understand what you’re doing. We’ve outlined below the difference between local and global muscles, to help you perform core work safely and effectively.
What Is the Core?
Your core is a shorthand way of referring to all the muscles of your lower back/pelvis/hip area. It’s where your centre of gravity is located and where movement begins. A strong core stabilises the spine and pelvis and supports you as you move. The core has 29 pairs of muscles that fall into two categories:
1) Local Muscles: Think of your local muscles as the deeper muscles, the ones close to the spine and responsible for stabilisation. They don’t have much ability to move the joints. The local muscles are further broken down into primary and secondary categories. The primary local muscles are the Transverse Abdominus and Multifidi (the two most critical muscles for providing stability). The secondary local muscles are the Internal Obliques, Quadratus Lumborum, Diaphragm and Pelvic Floor muscles.
2) Global Muscles: The global muscles are the outermost layer of muscle—they’re the ones you can feel through your skin. They’re responsible for moving joints. The global muscles in the core are the Rectus Abdominus, External Obliques, Erector Spinae, Psoas Major and Iliocostalis.
The core should operate as an integrated functional unit, with the local and global muscles working together to allow easy, smooth, pain-free movement. When the muscles work together optimally, each component distributes, absorbs and transfers forces. The kinetic chain of motion functions efficiently when you do something dynamic, like exercise or run.
An injury to one of the core muscles usually means an episode of lower back pain. When that happens, the deep stabilizers change how they work as a way to compensate for the injury and protect the area. The stabilisers now have delayed action; they’re turned on only after you move, instead of as you move. Because now they’re not functioning as they should, the brain recruits the global muscles to compensate. That causes a core imbalance. The result: pain in the lower back, pelvis and glutes (the big muscles you sit on).
Exercises designed to help get your core muscles back in balance are the best way to prevent re-injury and avoid lower back pain. Traditional abdominal exercises are often recommended to strengthen the global muscles. These exercises can actually increase pressure on the lower spine. Similarly, traditional lower back hyperextension exercises meant to stretch out the lower spine also may actually increase pressure on it. A better approach to preventing lower back pain is restoring stability with the core exercises below.
The abdominal brace activates all the contracting muscles in the abdominal wall. This exercise strengthens the connection between the global muscles and the deep local muscles. This helps restore the balance between them and improves spinal stiffness.
To get an idea of how the muscles in your core work, place your thumbs in the small of your back on either side of your spine. Next, do a hip hinge: bend forward from the hips about 15 degrees. You should feel the muscles in your lower back move as you bend and stand back up again.
To do the brace, stand upright and suck in your stomach, as if you were about to get punched. Hold that for 10 seconds, then relax. Repeat 20 times; do three sets.
You’ll know you’re doing the brace correctly if you poke your extended fingertips right into your side below your ribs and then brace. You should feel the muscles move under your fingertips.
Curl-ups train the Rectus Abdominus, the long abdominal muscle that runs vertically from your breastbone all the way down on both sides of your bellybutton.
Start by lying on your back with your hands palm-up beneath your lower back. Bend one leg and put the foot flat on the floor; extend the other leg, perform the abdominal brace. Hold your head and neck stiffly locked onto your ribcage - imagine them as one unit. Lift your head and shoulders slightly off the floor by about 10 centimetres and hold that position for 20 seconds. Your elbows should touch the floor while you do this.
Relax and gently lie back again and repeat 10 times. Switch legs and repeat 10 times again. Do three sets.
Tip: If you experience neck discomfort doing this, push your tongue against the roof of the mouth to help stabilise the neck muscles. If you experience pain in your low back try bending both knees.
Lying on your back with your knees bent, brace your abdominals then raise your hips up until you are in a straight line. Do not over arch your back. Keep your hips level and hold for 10 seconds then lower hips to the floor. Repeat 10 times.
This strengthens all of your core muscles due to abdominal bracing as well as your Glutes and Hamstrings. These muscles become weak from sitting too much.
This exercise is great for training the back extensors, including the Longissimus, Iliocostalis and Multifidus.
Start on your hands and knees (quadruped position). Raise and extend the opposite arm and leg simultaneously. Hold for eight seconds, then return to the quadruped position. Repeat eight times, then switch arms and legs and repeat for ten reps. Do three sets.
All the muscles of the core must work together to produce efficient and effective movement. The core is the centre of the body’s motion—training it is a critical part of any exercise routine.