Injury Prevention 101: Core Stability

In this article I summarise the main points from the second episode of the Injury Prevention series which is all about core stability and how it influences lower limb injuries. The other topics that I’ll cover include position sense, glute med, glute max, hamstrings, quadriceps and calf.

In this article:

• What’s your core and why is it important?

• The deep core muscles

• The superficial core muscles

• What is the perfect back/pelvis position?

• How to train the core effectively

• Nail the basic core exercises

• Download the core stability exercises

What’s your core and why is it important?

Most people know that your stomach muscles are part of your core, but it’s actually a lot more than that. Your core muscles include all the muscles around your pelvis, trunk, back and shoulder girdle.

These muscles all have to work together to provide a stable base so that your arms and legs can move in a coordinated way.

Imagine your arm or leg is a catapult and you want to use the catapult to shoot at a target. If the catapult is standing on a solid concrete base (your core), you can aim it accurately and it will move in a predictable way so that you hit the target every time. If, however, the catapult is standing on a block of jelly (poor core stability), it’s impossible to accurately aim the catapult and it will move in a slightly different way every time that you fire it.

From the above example it is clear that a lack of core stability will affect how your legs move when you exercise. It’s therefore no surprise that the research has shown that poor core stability can predispose athletes to a range of lower limb injuries including ACL tears, other knee ligament injuries, patello-femoral pain or runner’s knee, medial tibial stress syndrome (shin splints) etc.

For this article, I’m going to focus on the core muscles around the pelvis, trunk and lower back as I’m only interested in lower limb injuries for now. The muscles in these areas can roughly be divided into 2 layers namely the deep and superficial layers.

Despite all the research that has gone into this area we’re not yet exactly sure how the core muscles work and I’m going to provide a very simplified explanation below.

The deep core muscles

Think of this layer as providing the main stability to your spine and pelvis. They don’t create any movement when they contract, but instead increases your intra-abdominal pressure which helps to stabilise your spine.

They have to fire milliseconds before the other muscles and include the pelvic floor muscles, transverse abdominus (deep stomach muscles) and multifidi (deep back muscles). That’s why you have to work on isolating these muscles, before you move on to more taxing core exercises.

The superficial core muscles

These are the large muscles e.g. your erector spinae, obliques and rectus abdominus muscles. They play an important role in core stability as they have to ensure that your core moves in a controlled way.

Core stability is not just about having abs of steel in static position e.g. the plank. We are constantly moving and we have to strengthen and train our core muscles to effectively control our trunk and pelvis throughout the full range of movement. For examples, when you walk your trunk and pelvis rotates as your legs move and arms swing. This is normal and needed to move effectively. An example of poor core stability would be if someone allows their pelvis to tilt forward excessively or their trunks to side bend when they walk.

What is the perfect back/pelvis position?

There is no such thing as perfect alignment. We all have unique bodies and no 2 peoples' bones and muscles are exactly the same. This said, there are some broad parameters that are seen as “ideal”:

1. Your lumbar spine should have a gentle curve.

2. Your pelvis should not be tilted severely forward. If this is the case you will likely also have an excessive curve in your lumbar spine.

3. Your pelvis should not be tilted all the way back. If this is the case your will likely also have a flat lumbar spine with nearly no curve.

4. When you stand on one leg, your pelvis should remain level (one side should not drop) and it should not tilt forward or backwards.

5. When standing on one leg your trunk should remain upright and not lean to one side.

How to train the core effectively

Step 1: You have to start by teaching yourself how to move your spine and pelvis segmentally and find your neutral spine position. As discussed above, your neutral position is where your lumbar spine has only a gentle curve. The Cat/Camel exercise (see below) is great for teaching you segmental movement.

Step 2: The deep layer of your core muscles should always fire before the big superficial muscles kick in and the next step is to learn how to isolate these. When you contract your pelvic floor muscles, they usually automatically activate the multifidus muscles in the back and the transverse abdominus muscles in your stomach. I’ll explain how to do this in detail below.

Step 3: Once you can effectively find your neutral spine and activate your deep core muscles, it’s time to start adding in movement. The Toe Taps level 1 exercise is a great exercise to teach you how to maintain a stable back and pelvis while moving your legs. This is very important, because you want your back and pelvis to remain in good positions regardless of what your legs may be doing.

Step 4: From this point on, you can slowly make the exercises harder and more difficult and also incorporate complex movements as long as you always ensure that you activate/contract your deep core muscles first. The Toe Taps level 2 and 3 are good progressions.

Nail the basic core exercises

Cat/Camel

Aim: To teach you how to move your spine and pelvis one segment at a time.

• Start on all fours with your back straight, hands under the shoulders and knees under the hips.

• Imagine you have a tail attached to your bottom.

• Using your stomach muscles, tuck your tail between your legs and continue the movement with the rest of your spine so that your whole spine is curled up to the ceiling.

• Now reverse the movement by sticking your bottom up to the ceiling and curling your spine down to the floor so that you make a hollow in your lower back.

• You should initiate the movement from the pelvis and lower back and follow it with the rest of the spine.

• Do 10 times

Activating the deep core muscles

Aim: Your deep core muscles should contract before the rest of the core. This exercise will teach you how to isolate them.

Research has shown that when you contract the anterior pelvic floor muscles (those are the ones that stops you from urinating and wetting yourself), you also automatically contract the transverse abdominus muscle. Similarly, when you contract the posterior pelvic floor muscles (those are the ones that stops you from farting in public), you automatically activate the multifidus muscles in your back.

So we can use the pelvic floor muscles to activate the rest of the deep core muscles.

• Lie on your back with your knees bent and your lower back in a neutral position.

• Contract your anterior pelvic floor muscles by imagining that you’ve got a massive wee and you don’t want to wet yourself. For men, it’s also that sensation that you get when you walk into very cold water and everything down there tries to pull up and away from the cold.

• At the same time contract your posterior pelvic floor muscles by imagining you have wind and you don’t want to fart in public. It’s not squeezing your bum cheeks or glutes. You should just tense the muscles around your anus without tensing your glutes.

• The key to getting this right is to contract these muscles gently and slowly at first. If you do a quick hard contraction, the other stomach muscles usually kicks in.

• Make sure that your neck and chest is relaxed and that you’re not tensing the rest of your body.

• Hold the contraction for 10 sec while breathing normally.

• Repeat at least 10 times and practise this throughout the day in all positions e.g. sitting and standing as well. It can be hard to isolate these muscles at first but practise makes perfect.

Toe Taps level 1

Aim: To teach you how to maintain a stable back and pelvis while your legs move freely.

• Starting position: Lie on your back with your knees bent. Some people find it useful to place their hands under their lower backs so that they can feel if it moves. Use your lower stomach muscle to press your lower back flat onto the floor or onto your hands. Your chest and neck should be totally relaxed.

• Movement: Engage your core by recruiting your pelvic floor and lower stomach muscles. Lift one leg up to 90 degrees hip flexion, keeping the knee bent. Keep your back and pelvis completely still at all times. Then slowly place the foot back on the floor and repeat with the other side.

• Check that: Your pelvis does not twist and lower back DO NOT LIFT off the floor as you lift and lower your foot. I find it best if you concentrate on making sure that you feel the pressure of your back pushing into your hands, rather than thinking about lifting the leg.

• Aim: 2 sets of 10 lifts each side

Once you find this exercise easy, move on to level 2.

Toe Taps level 2

Aim: To teach you how to maintain a stable back and pelvis while your legs move freely. It’s just harder than the exercise above.

• Starting position: Lie on your back with your knees bent. Some people find it useful to place their hands under their lower backs so that they can feel if it moves. Use your lower stomach muscle to press your lower back flat onto the floor or your hands. Your chest and neck should be totally relaxed.

• Movement: Engage your core by recruiting your pelvic floor and lower stomach muscles. Lift one leg up to 90 degrees hip flexion, keeping the knee bent. Keep your back and pelvis completely still at all times. Then lift the other leg up to join the first. Now slowly place your first leg back on the floor followed by the other one.

• Repeat, but start with the other leg first.

• Check that: Your pelvis does not twist and lower back DO NOT LIFT off the floor as you lift and lower your foot. I find it best if you concentrate on making sure that you feel the pressure of your back pushing into your hands, rather than thinking about lifting the legs.

• Aim: 2 sets of 10 lifts

Once you find this easy move on to level 3.

Level 3: Single leg stretch

Aim: To strengthen the core muscles and teach you how to maintain a neutral spine and pelvis while moving your legs.

• Starting position: Lie on your back with your knees bent and your lower back flat on the floor.

• Movement: Engage your core by recruiting your pelvic floor and stomach muscles. Slowly straighten one leg out while you make sure that YOUR BACK STAYS ABSOLUTELY FLAT ON THE FLOOR. Only straighten the leg as far as you can control your back e.g. if you feel your spine lifting off the floor when your knee is half extended, only extend it half way. As you get stronger, you can then straighten your leg out further.

• Slowly alternate legs.

• Check that: Your back stays absolutely flat on the floor throughout the exercise. Do not rush this exercise – it is more difficult to do it slowly.

• Do 10 reps, Rest 1 minute, Do 3 sets

• Build up to 20reps x3 sets

In this video PT Timmo demonstrates some more core exercises that you can do in the gym.

Download the core stability exercises as a PDF

Need more help with your injury? You’re welcome to consult one of the team at SIP online via video call for an assessment of your injury and a tailored treatment plan.

About the Author

Maryke Louw is a chartered physiotherapist with more than 15 years' experience and a Masters Degree in Sports Injury Management. Follow her on LinkedIn or ReasearchGate

References:

1. De Blaiser C, Roosen P, Willems T, et al. Is core stability a risk factor for lower extremity injuries in an athletic population? A systematic review. Physical Therapy in Sport 2018;30:48-56. doi: 10.1016/j.ptsp.2017.08.076

2. Roussel NA, Nijs J, Mottram S, et al. Altered lumbopelvic movement control but not generalized joint hypermobility is associated with increased injury in dancers. A prospective study. Manual therapy 2009;14(6):630-35.

3. Verrelst R, De Clercq D, Vanrenterghem J, et al. The role of proximal dynamic joint stability in the development of exertional medial tibial pain: a prospective study. Br J Sports Med 2013:bjsports-2012-092126.

4. Zazulak BT, Hewett TE, Reeves NP, et al. Deficits in Neuromuscular Control of the Trunk Predict Knee Injury Risk: Prospective Biomechanical-Epidemiologic Study. The American journal of sports medicine 2007;35(7):1123-30.