Unveiling Your “Core”: Demystifying This Amazing Muscle Group !

Finally a simple understanding of our “Core Muscles” and their importance within our everyday life!

When it comes to fitness and overall well-being, the term “core muscles” is frequently loosely tossed around. So what exactly are these muscles, and why are they so important to us and our day-to-day living? As we embark on this exploration, let’s uncover the secrets and unravel the vital roles they play in supporting your body.

What muscles make up the core?

A major misconception that is thrown around is the considered muscles within your “core muscles”. Being able to gain clarity on this will facilitate effective prescription in building a strong core. Comprising of all the muscles that act and attach to the spine or pelvis, the three categorised groups involve:

1. Abdominal Muscles – Rectus Abdominus, Internal Obliques, External Obliques & Transverse Abdominus.
2. Posterior/Back Muscles – Thoracolumbar, Lumbar, Lateral Thoracolumbar & Latissimus Dorsi
3. Lower Extremity Groups – Gluteal muscles, Adductor muscles, Hip Rotators, as well as Hamstring & Hip flexor muscles.

Read throughout this blog to delve deeper into the specifics of each considered group and its further muscles!

What is the role of your core regarding health and fitness?

Core Muscles Impact Performance, Movement Efficiency, Protect Internal Organs, And Help Iwht Posture

The role of your core regarding fitness and general health circumstances is critical, rendering these muscles indispensable to the overall makeup and performance of your body. It is not simply labelled the ‘core’ because it is located at the centre of your body; rather, it is a crucial component of our musculoskeletal system that plays a vital role in various movements and functions.
Firstly, appropriate core function aids in stability and posture, particularly within the hips and spine, thereby reducing the likelihood of musculoskeletal imbalances and recurrent pain (in particular lower back pain).
Additionally, being strong in this area facilitates greater movement and flexibility, as well as enhanced balance and coordination. These elements, when working in tandem, allow for greater movement efficiency, effectiveness, and overall performance. Finally, a robust core not only helps protect internal organs but also contributes to an overall healthy balance.

What is the best way to strengthen your core?

Effective core training involves exercises that target the appropriate muscles collectively, providing strength, stability, and balance to the entire region. As mentioned, your core is made up of numerous muscles and muscle groups that should be worked appropriately through a variety of different exercises.
Trying to keep this as simple as possible to get started, we have split these into our three main groups, with exercises potentially following:

1. Abdominal Muscles: Dead Bug → Russian Twist → Bicycle Crunches
2. Posterior/Back Muscles: Bird Dog → Side Plank → Bent Over Row
3. Lower Extremities: Deadlift → Squat → Bulgarian Split Squat

Following these exercises in a progressive order will help allow for a safe yet effective progression in building the appropriate muscles to create a strong core. Read on and follow future blogs for further information and exercise progressions that can be implemented into your training regime!

Defining the Core Muscles:

Your core muscles are not just a singular entity but a group of muscles that work together to provide stability, balance, and support to your entire body functions. They comprise of all the muscles that act and attach to the spine or pelvis. They are primarily within your torso, however these also include numerous muscles below your pelvis.

These muscles can be categorised into three (3) main groups:

Abdominal Muscles
- Commonly mistaken for your core, your abdominals are made up of several different muscles that are an important component of your core, however, are not the only ones.
- The four main muscles found within your abdominal region comprise;
  - Rectus Abdominis – Allows for flexion of the spine. High activation during a ‘sit up’ exercise
  - External Obliques – Facilitates trunk flexion, lateral flexion and rotation. High activation during a ‘Russian twist’ exercise.
  - Internal Obliques – Works in conjunction with the External Obliques to aid in lateral flexion and rotation.
  - Transverse Abdominis – Helps provide spinal support and abdominal tension. Worked best during a ‘dead bug’ exercise.
Posterior / Back Muscles
- Another common misconception is that your core muscles are only found on the anterior, or front part, of your body. This is not the case, as your posterior, or back part of your body also holds significant value in the makeup too. Keeping this area strong aids in reducing potential imbalances, which will help reduce the likelihood of injury and facilitate greater movement efficiency and effectiveness. Core muscles within the posterior chain comprise:
  - Thoracolumbar Muscles
    - Consisting of your iliocostalis, Longissimus, and Spinalis muscles, collectively known as your ‘Erector Spinae’, these muscles help extend and laterally flex your trunk, as well as support the spine.
  - Lumbar Muscles
    - Muscles again comprising of your Erector Spinae group, as well as your Quadratus Lumborum (QL) help provide necessary stability to the hips and spine to create and maintain healthy movement patterns.
    - Another pivotal muscle is the Multifidus, which is located within the lumbar and thoracic region of your spine. This muscle helps create spinal support and offers deep core stability.
  - Lateral Thoraco-Lumbar muscles
    - Finally, your thoracic-lumbar muscles are very similar to the previously mentioned External Obliques, providing support during lateral flexion and rotation. In saying this, it is important to strengthen the lateral, or side area of your core, to create equilibrium within.
  - Latissimus Dorsi
    - The final muscle involves your Latissimus Dorsi, AKA your “Lats”. This large muscle may come as a surprise, but its involvement mustn’t be overlooked. Not only due to its role in helping with spinal support, but your lats also hold major engagement in vital movements such as climbing/pulling-up, or swinging, which have an indirect correlation to the need for a strong core.
    - As well as this, your lats impose on shoulder and scapular movements, which are vital for postural health, further holding indirect contributions to correct spine and core alignments.
Lower extremities
- As mentioned, the make-up of your “core muscles” are any muscles that act and attach to the spine or pelvis. As a result, your lower extremity muscles fall into this category and have more influence than you may think!
- Lower extremity muscles impact the core for various reasons but fall under the holistic thought that there is heavy involvement through their functional connections and interactions. This concept will be delved into, but for the time being, let’s clarify the relevant lower extremity muscles.
  - Gluteal Muscles – Mainly consisting of your Gluteus Minimus, Medius and most importantly, your Gluteus Maximus. The primary impact these have on the core is due to the large role involved in hip movement and stability. Pelvis stability must also not be overlooked.
  - Adductors – The three muscles the Adductor Longus, Magnus and Brevis make up your adductors. Although they don’t bear as much impact as the gluteal muscles, your adductors indirectly influence your core due to their heavy involvement in maintaining pelvic stability and positioning. With this in mind, high levels of core stability will subdue.
  - Hamstrings and Hip Flexors – The main muscles that make up the hamstrings are the biceps femoris, semimembranosus, and semitendinosus. Moreover, the muscles considered within your hip flexors involve the iliopsoas, rectus femoris, and sartorius. Similarly to the adductors, your hamstrings and hip flexors indirectly influence core strength by impacting the positioning and stability of the pelvis, as well as spinal support. Hence through an indirect correlation, core strength is heavily influenced through pelvic and lumbar stability to allow for efficient and effective movement patterns.
  - Hip Rotators – Hip rotators being your piriformis, gemelli and obturator muscle groups all hold a role considered within your core due to their interconnectedness throughout. Similarly to the previous groups, this holistic group helps stabilise the pelvis to keep it neutral, allowing for correct positioning and reduced likelihood of strength imbalances and further poor core engagement.

Functions of the Core Muscles:

Now that we’ve identified the key players in your core, let’s delve into the functions that make these muscles indispensable to your body’s overall performance.

Stability and Posture:
- The core muscles act as a stabilizing force, helping you maintain balance and good posture. Whether you’re sitting at a desk, standing, or engaging in physical activities, being strong within is essential for preventing slouching and reducing the risk of back pain.
Spinal Support:
- Your core muscles, particularly the Transverse Abdominis and Erector Spinae, work together to support the spine. This support is crucial for preventing injuries and promoting spinal health.
Movement and Flexibility:
- Strong core muscles facilitate a wide range of movements, from bending and twisting to lifting and reaching. Whether you’re participating in sports, exercising, or performing everyday tasks, a well-conditioned core enhances your overall flexibility and agility.
Balance and Coordination:
- The core is your body’s central point of gravity. Being well-developed in this area contributes to better balance and coordination, reducing the risk of falls and enhancing your overall athletic performance.
Protecting Internal Organs:
- The Transverse Abdominis acts as a protective shield for your internal organs. A strong core helps stabilize the pelvis and shields the lower back, providing additional support to vital organs.

Strengthening Your Core:

Now that we understand the significance of core muscles, how can we strengthen them? Incorporating targeted exercises into your fitness routine is key. Below are some effective exercises for each group of core muscles, with video demonstrations:

Abdominal Muscles
- Dead-b ug → Russian Twist → Bicycle Crunches
Posterior / Back Muscles
- Bird Dog → Side Plank → Bent Over Row
Lower Extremities
- Deadlift → Squat → Bulgarian Split Squat/Rear Foot Elevated Lunge

There has been and continues to be a huge body of research regarding the best exercises for increasing core strength. The most recent information indicates that greater recruitment, thus improvements are achieved via large compound exercises such as squatting, and deadlifts. Considering this, it is critical to incorporate these lifts into your routine wherever possible.

Remember to ensure the safety and technique of these exercises before increasing volume and quantity. Further, consider following our future blogs for further information and exercise progressions that can be implemented into your training regime to help continue to build a stronger core session by session!

Dead-Bug

Russian Twist

Bicycle Crunches

Bird Dog

Side Plank

Bent Over Row

Deadlift

Squat

Rear Foot Elevated Lunge / Bulgarian Split Squat

Conclusion:

Your core muscles are the unsung heroes of your body, providing the foundation for strength, stability, and overall well-being. Whether you’re an athlete aiming to improve performance or someone looking to enhance everyday movements, understanding and nurturing your core muscles should be a fundamental part of your fitness journey. So, here’s to a strong and resilient core that supports you in all your endeavours!

If you need further guidance, please reach out to us and take advantage of a free 15-minute telehealth consultation with our exercise physiologist.

Written by Paolo Mitry, an Exercise Physiologist at Activ8 Health Club

Exercise Recommendations – What should we be achieving?

Importantly see if you are meeting the Current Exercise Recommendations!

There is a lot of information and conflicting information as such out there regarding the current exercise recommendations. Furthermore, these keep changing over the years which makes it even harder to know. It also depends on many other factors including medical conditions (such as Cardiovascular Disease, Diabetes, Osteoporosis, Endometriosis, Chronic Pain) age level, gender and even the intensity of exercises undertaken throughout the week. In saying that, we have tried our best to give you the latest information (Current to 2023) regarding the most common situations in the simplest digestible (get it…?) form.

Within the apparently healthy population (a state of complete physical, mental and social well-being and not merely the absence of disease and infirmity as stated by WHO), individuals are unsure if they’re hitting the recommended amount of weekly exercise minutes. Due to this, a greater case in the development of lifelong conditions such as diabetes and heart disease has occurred, leading to a rise in global levels of sickness and death.

Needless to say, exercise is an amazing way to help prevent, manage or delay the onset of these prevalent conditions, along with so many more benefits, but you may be thinking, what exactly should you be doing, and how many minutes you should be aiming for? Well, this blog will uncover all the information you need to know!

What are the current rates of physical inactivity, and what general benefits does exercise hold?

Physical inactivity is a term that is not uncommonly used, particularly among Australians. Due to the natural demands of life such as work, children/family commitments and hobbies, along with other aspects such as injury, individuals may struggle to have the time, motivation or desire to partake in exercise, which is completely understandable! In saying this, it is thought that nearly 60% of Australian adults, and 70% of pregnant women do not meet the recommended weekly exercise minutes resulting in an increased likelihood of developing lifelong chronic conditions.

Enough about the negative side of things though, as you may be thinking what the benefits of being physically active are. Well, similarly to the negative impacts of physical inactivity, exercise has flow-like effects too! Being physically active has the overarching stem of reducing the likelihood of developing chronic conditions as mentioned, but there is much more to delve into.

Exercise holds numerous benefits both physically, mentally and even socially! Starting with the mental benefits, exercise is a prime way to release our happy hormones called endorphins. The release of these happy chemicals helps reduce levels of stress and increase feelings of well-being, which in tandem helps reduce levels of depression and anxiety. Furthermore, the physical benefits of exercise come in abundance, primarily reducing the risk of obesity, which reduces or maintains blood pressure, total cholesterol and blood sugar levels. Further improvement in quality of life, sleep quality and energy levels also occur. This then can be linked to the overarching stem of reducing the likelihood of developing chronic conditions!

What are the specific benefits of each exercise modality?

There are three (3) main modalities of exercise, them being cardiovascular, resistance, and flexibility. Each of these modalities holds various and numerous benefits, but are a fantastic mixture when used in tandem with each other!

Cardiovascular
- This training modality had excessive links to greater heart and lung health, along with reducing levels of overweight/obesity, blood pressure, total cholesterol and low-density lipids whilst increasing levels of high-density lipids and insulin sensitivity, also keeping blood sugar levels at a healthy range
Resistance
- Resistance training has excessive links to increasing your resting metabolic rate, which allows for greater energy burning when at rest, which helps prevent levels of overweight/obesity. Furthermore, this training modality helps combat the potential of falls and fractures due to the improvement of muscle strength and power, which can therefore help further support surrounding joints. Moreover, it also reduces the likelihood of osteoporosis due to the loading of your bones.
Flexibility
- Incorporating flexibility training into your life is vital in helping prevent injury by increasing the range your joints and muscles can move through. With this, it promotes efficient and healthy posture and movement patterns, thus increasing your ability to complete everyday tasks with greater ease.

Cardio Strength Flexibility — Exercise recommendations - what should we be achieving? 13

How many minutes of weekly exercise should I be achieving?

As mentioned, the ideal minutes are different between populations, so depicted in the table below are three subgroups associated with the apparently healthy population.

Apparently Healthy Adults and older Adults

Current Recommendations For Apparently Healthy Adults And Older Adults — Exercise recommendations - what should we be achieving? 14

2. Pregnant Women

Current Recommendations For Pregnant Woman — Exercise recommendations - what should we be achieving? 15

3. Individuals with Lower Back Pain

Current Recommendations Individuals With Lower Back Pain — Exercise recommendations - what should we be achieving? 16

Conclusion

In summary, it’s important to acknowledge that any amount of exercise, no matter how brief, is a step in the right direction toward a healthier lifestyle. However, when we delve deeper into the realm of fitness and well-being, we find that the most significant rewards, both for our physical and mental health, emerge when we commit to a more structured exercise routine.

The magic number to aim for is approximately 150 minutes of weekly cardiovascular exercise, ideally supplemented with resistance and flexibility training. This balance strikes a harmonious chord in our pursuit of overall wellness. Why, you ask?

First and foremost, cardiovascular exercise elevates our heart rate, strengthens our lungs, and enhances circulation, effectively boosting our cardiovascular health. This form of exercise, which includes activities like brisk walking, running, cycling, and swimming, plays a pivotal role in reducing the risk of heart disease, stroke, and hypertension.

On the other hand, resistance training, such as weightlifting or bodyweight exercises, empowers our muscles and bones. This crucial component of the ideal workout routine not only helps sculpt a toned physique but also fortifies our skeletal system. By engaging in resistance training at least a couple of times a week, we can actively combat the decline in muscle mass associated with aging and promote better metabolic health.

Flexibility training, often encompassed by practices like yoga or stretching exercises, enhances our range of motion and helps prevent injuries. It keeps our joints supple and muscles pliable, reducing the risk of strains, sprains, and other physical mishaps.

But perhaps the most compelling reason to strive for this comprehensive exercise regimen is its role in disease, illness, and injury prevention, management, and delay. Regular exercise, when combined with a balanced diet and other healthy lifestyle choices, can be a formidable ally against chronic diseases like diabetes, obesity, and certain types of cancer. It helps manage conditions such as arthritis and osteoporosis, improving overall quality of life. Moreover, it aids in the prevention of injuries by enhancing our physical resilience and reducing the risk of accidents.

In essence, while any minute of exercise is undoubtedly better than none, it’s the dedication to a well-rounded exercise routine that truly unlocks the extensive benefits for our body and mind. It’s a commitment to your health, longevity, and vitality. So, as you embark on your fitness journey, remember that striving for approximately 150 minutes of weekly cardiovascular exercise, complemented by resistance and flexibility training, is a powerful formula that can lead to a healthier, happier you, while simultaneously delaying, managing, or preventing a host of diseases, illnesses, and injuries.

Written by Accredited Exercise Physiologist Paolo Mitry from Activ8 Health Club

Exercise Myths Quickly Unveiled Here and Now!

I bet you have heard all these before….!

We’ve heard them all before, but with so much content and opinion out there, it can be difficult to separate fact from fiction. In this blog, we shed light on seven common myths about exercise.

Is “no pain no gain” with exercise correct?

Absolutely not!
Whilst feeling uncomfortable is associated with high-vigorous exercise, it does not have to be achieved to gain improvements in health and fitness.
You achieve different health benefits with different types of exercise and intensity levels, with some critical improvements obtained ‘without pain’.

Can I “spot reduce” fat with exercise?

Absolutely not!
Exercise and nutritional changes may reduce total body fat when done correctly, however, there isn’t a way to target specific areas. There are many elements that influence is comprising of age, genetics, exercise type, diet, medication, medical conditions etc

Sit-ups will reduce fat around my abs

Unfortunately, this isn’t correct!
Sit-ups will help with building muscle mass and strength around your abdominals, however, they will not reduce fat. If you are looking for a leanier look, you will need to reduce your overall body fat.

Myth 1: “No pain, no gain”

Whilst evidence demonstrates increased benefits of exercise in conjunction with an increase in intensity, there is no need to overdo it. A consistent mix of light to moderate-intensity exercise each week that is performed safely is preferred over inconsistent maximal efforts. If you are inactive, starting out with a daily 30-minute brisk walk can deliver significant health benefits, and you’re more likely to stick with it too.

The current exercise recommendations as stated by the Australian Physical Activity Guidelines, ESSA and the American College of Sports Medicine (ACSM) recommends a weekly accumulation of 150 minutes of vigorous or 300 minutes of moderate-intensity activity or a combination of both. Health benefits include reducing the risk of heart disease, type 2 diabetes, and some cancers, as well as regulation of blood sugar, blood pressure, and cholesterol, weight maintenance, and assistance of weight loss. ^(1,2)

Myth 2: Dieting, not exercise is the only way to weight loss

Fad diets with caloric or nutrient restriction are often short-lived and may lead to even more weight gain in the long term. In reality, the key to sustainable weight loss is to create healthy eating habits that can be maintained with a lifestyle change⁽³⁾. Those who restrict calories, or who abstain from eating altogether could be doing more harm than good. The weight that is lost in the first 4-6 weeks from Fad dieting is a majority of the time lost water and lean mass, with further reduction in your metabolism in conjunction with muscle atrophy (loss). Preserving lean tissue through exercise maintains the body’s metabolism, in order for energy (and calories) to be expended.

Therefore, we should focus not on “weight loss”, but rather “fat loss”, and incorporate consistent exercise for lean tissue preservation in any weight management program. It is also critical that your lifestyle is modified to maintain and achieve long-term results. Whilst significant fat reduction can be achieved through diet, exercisers also gain numerous additional health benefits such as insulin sensitivity for diabetes, cardiorespiratory fitness improvements and reduce risk of cardiovascular heart disease.

Myth 3: You can “spot reduce” fat with exercise

This long-standing myth is still promoted in magazines and online. Put simply, you won’t get sculpted, fat-free abs by doing crunches alone. Exercise and nutritional changes may reduce total body fat when done correctly, however, there isn’t a way to target specific areas.

Recently, aerobic exercise has been associated with a preferential reduction in abdominal fat,⁽⁵⁾however further research is required. Further findings could have significant implications in public health, as waist circumference is considered a risk factor for chronic disease.

Crunches Do Not Reduce Fat! — “Sit-ups do not result in weight loss”

Myth 4: Long training sessions are the only way to build endurance

Contrary to popular belief, it’s not all about clocking up hour after hour on the pavement or bike to improve your cardiopulmonary endurance. It has been well established that high-intensity interval training (HIIT) is just as effective a method to increasing performance as is it is for longer continuous bouts. Not only is interval training a time-saver, but it also provides variety and challenges to your training program and energy systems.

An emerging form of interval training, known as anaerobic or sprint interval training (SIT), is also showing potential in producing improvements in endurance through even shorter training bouts, where intervals of supra-maximal efforts are performed. ^(6,7)

Myth 5: Your genes control your weight, and there’s not much you can do about it

Yes, we all have different body shapes but does a genetic tendency for weight gain mean indefinite obesity?

A 2010 study has found that amongst women identified with a genetic predisposition for obesity, the group with homozygous gene expression actually experienced the greatest weight loss from exercise. ⁽⁸⁾ As we know, in addition to weight management, exercise also delivers immense health benefits and reduces the risk of chronic disease. Research in this area is ongoing, but for now, it’s encouraging to find that achieving a healthy weight is not out of your control.

So what’s the take-home message here? well, there are many factors that influence weight loss and gain and some will have to work harder than others. This doesn’t give anyone an excuse to not strive for improvements and/or reach their goals!

Myth 6: Exercise cancels out sedentary time

We now realise that sedentary time in modern society is having serious health implications, with Australians being sedentary for 7 to 10 hours each day (outside of sleeping). ⁽⁹⁾ Sedentary lifestyles are the leading cause for most chronic diseases and surprisingly, sessions at the gym do not compensate for extended periods of sitting. This means that with additional exercise, we must also spend less time sitting at work and at our homes. Even if the current recommended physical activity guidelines are met, interrupting and minimizing sedentary time is still required to reduce the health risk. ⁽¹⁾ So start getting creative and walk to the printer, try a sit/stand desk to change your position, park further away and walk to work, catch one bus stop further so you have to walk there and encourage walking meetings with colleagues. You can read more about incidental physical activity in our blog.

A Sedentary Lifestyle Is The Next Smoking! — A sedentary lifestyle is the next smoking!

Myth 7: Cardio is enough for good health

Whilst walking, jogging, cycling, and swimming are well established as beneficial exercises, is there more we can do for optimal health?

It’s now recognised that resistance training is valuable for all ages, especially as we age. Biologically, building and maintaining muscle tissue is essential for energy metabolism, reducing the risk of chronic disease and falls prevention. Furthermore, functional benefits such as improvement in joint integrity, posture, mobility, and balance all become increasingly important with aging.

In addition to aerobic exercise, the latest Australian physical activity guidelines and ESSA now recommend 2-3 days per week of muscle-strengthening activity. ⁽¹⁾Strength training doesn’t have to be complicated; it can be done at home with little or no equipment. A couple of times each week, try fitting in some bodyweight exercises such as push-ups, lunges, and squats. Read our easy home-based exercises blog for further examples.

Written by Trent Carruthers – Exercise Physiologist 

References

1. Commonwealth of Australia (2014). Australia’s Physical Activity and Sedentary Behavior Guidelines for Adults (18-64 years).
2. Pescatello, Arena, Riebe, Thompson (Eds.) (2014), General Principles of Exercise Prescription. In ACSM’s Guidelines for Exercise Testing and Prescription. (pp 166-177).
3. Gögebakan, O., Weickert, M. O., Holst, C., Saris, W. H. M., Astrup, A., Pfeiffer, A. F. H., on behalf of DiOGenes. (2011). Effects of weight loss and long-term weight maintenance with diets varying in protein and glycemic index on cardiovascular risk factors: The diet, obesity, and genes (DiOGenes) study: A randomized, controlled trial. Circulation, 124(25),2829-2838. doi:10.1161/CIRCULATIONAHA.111.033274
4. Ross, R., Janssen, I., Dawson, J., Kungl, A.-M., Kuk, J. L., Wong, S. L., Hudson, R. (2004). Exercise-Induced Reduction in Obesity and Insulin Resistance in Women: A Randomized Controlled trial. Obesity Research, 12(5), 789-798.doi: 10.1038/oby.2004.95
5. Horowitz, J. F., Leone, T. C., Feng, W., Kelly, D. P., Klein, S. (2000) Effect of endurance training on lipid metabolism in women: a potential role for PPARalpha in the metabolic response to training. Am J Physiol Endocrinol Metab (279): E348–E355.
6. Stepto, N. K., Hawley, J. A., Dennis, S. C., & Hopkins, W. G. (1999). Effects of different interval-training programs on cycling time-trial performance. Medicine and Science in Sports and Exercise, 31(5), 736-741. doi:10.1097/00005768-199905000-00018
7. Kirsten A. Burgomaster, Scott C. Hughes, George J. F. Heigenhauser, Suzanne N. Bradwell, & Martin J. Gibala. (2005). Six sessions of sprint interval training increase muscle oxidative potential and cycle endurance capacity in humans. Journal of Applied Physiology, 98(6), 1985-1990. doi:10.1152/japplphysiol.01095.2004
8. Mitchell, J. A., Church, T. S., Rankinen, T., Earnest, C. P., Sui, X., & Blair, S. N. (2010). FTO Genotype and the Weight Loss Benefits of Moderate Intensity Exercise. Obesity, 18(3), 641-643. doi: 10.1038/oby.2009.311
9. Tilley, C., Sit less, move more: why Australia doubled its exercise guidelines, 12 March 2014. Accessed online Mon 26 Jan 2015.  http://www.abc.net.au/news/2014-03-11/physical-activity-guidelines-explainer/5295552