Should you include sit-ups and crunches in your training?

Should you include sit-ups and crunches in your training?

These exercises have been a mainstay of physical conditioning routines for as long as physical conditioning has been around. We all know that one person that starts their day off with a hundred (or other arbitrary number) sit-ups or crunches. We’ve been told for countless years that the best way to train your ‘abs’ is to do sit-ups or crunches in any number of different varieties…. but is it really that simple?
Let’s look at the exercises themselves. At their heart, sit-ups and crunches are built around the action of flexion of the spine. When we lay supine (facing up), we are using gravity to provide resistance against this flexion action. This places load on our rectus abdominis (commonly referred to as the ‘abs’) and to a lesser degree, the obliques (1). With this in mind, we can correctly draw the conclusion that these exercises can be used to strengthen or condition the ‘abs’ (dependant on rep ranges etc), and even cause hypertrophy (increased muscle size) of the ‘abs’ if the load is appropriate. So far so good, right? But is repeated flexion necessary, or even healthy?
For a number of years now, a large number of trainers, strength coaches, and physiotherapists have been moving away from prescribing or recommending these exercises to clients. The driving reason behind this change is the research conducted by spine biomechanist Dr Stuart McGill and his team at the University of Waterloo, Canada, who used in vitro testing of pig spines (which are very similar to human spines) to demonstrate that repeated flexion of the spine is highly likely to lead to disc pathologies (1). McGill’s findings were that high numbers of flexion movements in the spine ultimately lead to disc injuries such as herniation.
Not all health and fitness trainers have subscribed to McGill’s findings. His major opponents consider his use of porcine cervical spines with no active muscular attachments as not being representative of the moving spine in a living human. One of the major threats to disc health during movements, is the compressive force created by the contraction of muscles acting on the spine. As the muscles pull the spine in various directions, the compression on the intervertebral discs shifts, and becomes uneven which can lead to disc herniation. Biomechanical modelling predicts that up to 18% of this compressive force can be offset by the presence of intra-abdominal pressure (IAP) during spinal flexion (2).
These arguments are for the most part theoretical however, with no conclusive clinical evidence to support them – leading us to the conclusion that right now, the best research we have on the effects of repetitive flexion of the spine is Stuart McGill’s. Factoring in McGill’s research, alongside the correlation of genetics and spinal degeneration (3), it’s difficult to justify the prescription of crunch type exercises when lower risk, more practical training approaches exist.
Some organisations (such as the ADF, Police Departments etc) have a requirement for members to perform sit-ups or crunches in workplace fitness assessments. Our advice in this situation would be to only program the required number of sit-ups/crunches required to get you through your fitness test, and ensure you have prescribed exercises to train your spinal extensors to balance out the number of flexions you are performing (deadlift variations are a great way to do this).
As always, having an experienced professional to develop your training programs is the best way to ensure you are keeping a balance in your exercise prescriptions, and performing the safest possible exercises to address your needs.
(1) McGill SM. Low Back Disorders. Champagne, IL: Human Kinetics, 2002
(2) Stokes IA, Gardner-Morse MG, and Henry SM. Intra-abdominal pressure and abdominal wall muscular function: Spinal unloading mechanism. Clin Biotech (Bristol, Avon) 2010
(3) Battie ́ MC and Videman T. Lumbar disc degeneration: Epidemiology and genetics. J Bone Joint Surg Am 88(Suppl 2), 2006 

Fitness Myths iNformed

After discussing our last post on spring related aches and pains on radio last week (ABC 891 ‘Drive’ with Grant Cameron – wednesdays at 5.45pm) we’ve been told by a lot of people that they felt challenged to get out and get more active, which is fantastic!

However some of the approaches and concepts that people mentioned have needed a bit of guidance, so here are the top 5 typical fitness misconceptions that we often hear. Hopefully this will help you stay on a better, more informed path towards health and fitness!

  1. Spot fat reduction – we cannot target a specific body region for fat loss. eg. Situps to reduce abdominal fat. The body burns fat as a result of diatary modifications and/or exercise generally, and not from specific targeted areas. While some areas do lose fat quicker than others, this is hormonally and genetically predetermined. For more information on this check out an earlier post on doing sit ups to get a flat stomach
  2. Situps to strengthen the lower back – while abdominal strength is crucial for low back strength, the muscles that need to develop are those deep muscles of the abdominal region, typically known as the ‘core’. This does not include the rectus abdominis (RA) (or ‘six-pack muscle). The 6-pack is a superficial power muscle with little endurance and capacity for prolonged spine stability. In addition, the tuypical way of working it, crunches and sit ups, is a repetitive bending of the spine under load. Exactly the same movement that tends to hurt the back in the first place! stay tuned for a future post developing this argument further. In the mean time, if your abdominals need greater strength to protect your spine please see a quality exercise professional for guidance, as this is an area that if worked incorrectly, could hurt more than benefit form badly performed exercises.
  3. Weights bulk you up -of course doing resistance training (weights) correctly will increase muscle size strength and improve shape. However the progress is at best slow and requires significant effort. The most significant factors determining the speed and amount of muscle growth are the type of training you do, your nutrition, and hormonal levels. This last fact disadvantages females significantly due to their lower levels of testosterone and growth hormone. Interestingly we most often hear this concern from women! Body Buiders adhere to training routines similar to those of professional athletes (and many of them are just that), including 10+hrs in the gym weekly, very strict nutritional plans and hundreds of dollars on nutritional supplements and other ‘aids’. Unless you are willing to subject yourself to such a routine, you are in little danger of bulking up out of control!
  4. Pushing through pain & exercising when sick – have you ever exercised to ‘sweat out’ an illness/cold? firstly, pain beyond that normally experienced muscle soreness 24-36 hrs post exercise, is often a warning signal of a developing injury. training ‘through’ that will only increase the chances of you developing an injury. We recommend that you stop the activity that causes the pain and see a trusted health professional to rehab that weak ‘link’. We start all of our clients with what we call ‘foundation exercises’, which are designed to improve the function of postural and stabilising muscles and thus strengthen those ‘weak links’. In as far as ‘sweating out’ a cold: we know that long term, exercise improves immune function, but exercise has a short and acute supressing effect on the immune system. Exercise places a large energy demand on the body, which during a sickness, should be directed towards fighting that sickness. Exercise, then, while ill, palces a greater load on an already stressed immune system. the best thing would be to keep fluid intake high, eat a natural and colourful diet, and rest!
  5. All I have to do is exercise to lose weight – check out a previous post that goes into good depth about this argument/belief. To add to that information it is interesting to note how much exercise actually needs to be performed to ‘burn’ some common indulgences:


  • 2 GLASSES OF WINE are 850 kj & WILL TAKE YOU




  • 1x 55gm CHOC BAR IS 1200 kj & WILL TAKE YOU


  • 1 50gm PACKET OF CRISPS IS 1100 kj & WILL TAKE YOU


hmmm, food for thought!

Getting a ‘flat-stomach’!

This is a huge topic with many ramifications, so to give it the attention it requires I’m going to address it over a number of discussions over the next few weeks. This way we can start to put things in place one step at a time, and give you the time to ask any questions you need.

So here it is! I’d love to get your feedback, opinions and further questions on this!

Firstly one thing needs to be clarified. Many people do crunches to reduce the fat around their abdominal area. Fat CANNOT be spot reduced, meaning that you can’t choose where you will lose fat from, even if you focus your exercise (or scrubbing/loofaing) on that specific area. Fat loss is a chemical process that happens from the whole body.

So you will lose as much fat from your abdominal area from doing crunches as you are from squats. as a matter of fact you will lose more from the same number of squats, as you are using a larger muscle mass, and hence requiring more energy.

It’s worthwhile mentioning that adypose (fat) cells in the abdominal region are more labile. That is, they are typically the first to absorb fat and the first to lose it. But this is due to their chemical/physiological responses and not to the type of exercises we do. This is why we would tend to see guys with relatively lean legs and arms, but with a bulge around the abdominal area. And why women find it harder to lose fat from the stubborn hips and bum area. These fat cells truly are more stubborn!

So, the number one rule to achieving a flat stomach is to get rid of the covering over it! yes, its about becoming leaner. I guess most of us have heard the statement that ‘we’ve all got a six-pack, we just need to show it’. This is largely true. The shape of that six-pack (which is actually an eight-pack, as there are eight visible segments of the rectus abdominis behind its connective tissue) is largely genetically determined, but the leaner you are, the better it will look!

Next week I’m going to post a discussion on some recent and very high quality research that presents very interesting and exciting strategies to help us become leaner in a sustainable and achievable way, so make sure you stay tuned in!

So what should we take away from this weeks discussion: a) start to look at your dietary intake, because therein lies the answer to your ‘six-pack’, and b) spend the time you may have spent on crunches/sit-ups on ‘larger’ whole body exercises, or increasing your energy expenditure (out put) by doing some higher intensity cardio(vascular) exercise, such as fast walking, jogging, cycling, etc. Even a solid gardening session will do the trick! considering the rains we’ve had, and the current sun-shine, I’m sure your lawns could need a bit of attention. If not, I’m happy for you to exercise on mine!!

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