You're in a pump class at the gym, and you're bracing yourself to unleash a string of explosive box jumps. And then you hear those four words uttered that you've never really understood: 'Turn on your core'.
How does one actually go about this? And what are we 'turning on', anyway?
(Hint: it's a lot more than your abs).
"Your core essentially comprises all the muscles from your hips to your torso that coordinate limb function," physiotherapist Christine Fletcher, from Function Physio, told The Huffington Post Australia.
"It does include your abdominal muscles, but that's not all. Your core is also made up of your back muscles -- your 'multifidus' muscle, your spinal erectors and, to a lesser extent, your lower trapezius (traps) and latissiumus dorsi (lats) -- as well as your pelvic floor, or the dish of muscles that sit inside your pelvis."
How do we use our core muscles?
We're using our core everyday -- in ways you may not realise.
You're on a bus, and it's starting to jolt. As soon as your core feels a change in weight placement, it is going to jump in.
"Your core registers this change in weight placement and effectively turns on to sustain yourself from falling over -- and to calculate your next reactive move. In this way, it anticipates movements," Fletcher said.
"Functionally, your core is there to provide you with stability and balance, as well as acting as coordination between the upper and lower half or your body."
If you are not engaging your core muscles, other muscles will step in to compensate and you can potentially injure them if the load is too great.
Engaging your core helps your body to support your spine, so that the burden of supporting your body weight isn't just placed on your bones.
"If you are not engaging your core muscles, other muscles will step into compensate and you can potentially injure them if the load is too great," Fletcher said.
"You may experience lower back pain if you are using more of the upper muscles, or you may catch yourself in a hunched over position if your back postural muscles aren't turned on to keep you upright."
How does one 'activate' a muscle?
"We have over 600 muscles in our body, and a lot of them are voluntary. Whilst some are hard to voluntarily contract, a lot of them are quite easy to do so," Fletcher said.
"Turning on or activating a muscle means you are consciously contracting it. When you contract, you are sliding the muscles across each other, or pulling them together."
How does this happen?
"Nerves will create an impulse throughout the body and you can directly influence that by thoughtful action," Fletcher said.
According to Fletcher, engaging your core muscle also leads to improved function in various sports and activities.
"A strong core will set you up for reaping the optimal exercise. This is of great importance for soccer players who are often darting in different directions, which is anticipatory movement that relies heavily on stability," Fletcher said.
"Studies have also shown a stronger core helps with ACL (anterior crucial ligament) rehabilitation."
How should we go about it?
When it comes to core training, Fletcher says it is important to engage all aspects of your core.
"The whole point of your core is to work as a union and you'll gain optimal benefits in stability, balance and coordination," Fletcher said.
Your core should be activated in most movements, particularly in explosive ones, to allow the movement to occur in the first place.
"I love fit balls. Because you have an uneven surface, there is a lot of change in weight transfer. If you can work on stabilising in that situation, you are essentially mimicking your core activity."
Planks and side planks are effective core exercises -- as are pylometric movements such as box jumps or lunges.
"Your core should be activated in most movements, particularly in explosive ones, to allow the movement to occur. Even as you are doing your box jumps, think about whether your core is turned on. You might not necessarily feel it as much as you would in a crunch, but it's working."
How to crunch:
"A lot of people will over compensate when they attempt crunches. They'll often take a breath in and brace themselves, which just isn't functional and the contraction can't be sustained for long," Fletcher said.
"Building up strength in your abdominal muscles is still useful if you go about them in the right way. Activating your core means you are turning on the right muscles, so if you are feeling it in your core, you're on the right track.
"If you start to feel it in your spine or your hips, that is a sign that the load is too high and other muscles are taking over. Take it back to the basics."
With all of this being said, some core muscles remain easier to activate than others.
"It is easier to active your frontal parts, such as your abdominals, but with guidance and practice, you can start working those important back muscles, as well."
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