Fact or fiction – do sit-ups do more harm than good?

Accredited Exercise Physiologist, Kitty Chao, busts the myth around ‘spot reduction’ and questions whether sit-ups do more harm than good.


The mentality that the fitness industry has blanketed over the general population has caused a lot of people to think that there is such thing as ‘spot reduction’. Spot reduction refers to the fallacy that fat can be targeted for reduction from a specific area of the body and that it can be achieved through exercise of specific muscles in the desired area, such as exercising the abdominal muscles in an effort to lose weight in or around one’s midsection.

This ties in with my previous post about strength training myths, however not only does this concept apply to women but males too.


The most problematic thing that has been found with typical exercises programs is repeated lumbar flexion.

Far too often I have clients come to me wanting to do more ‘ab workouts’ and quote that they used to do ‘100 sit-ups a day’ and have lower back issues arising from it.

The most problematic thing that has been found with typical exercise programs is repeated lumbar flexion. This means bending forward at the lower spine. This act of bending the spine forward places a large amount of compressive force on the spine and can lead to injury.

It has been found that sit-ups can put hundreds of compressive forces on the spine. McGil has found that crunches and traditional sit-ups place 3,300 newtons the equivalent of 340 kg! of compressive force on the spine when bent in flexion. These forces can squeeze a bent disc’s nucleus to the point that it bulges – pressing on nerves and causing back pain, and potentially leading to a herniated disc.

The sit-up and back pain relationship involves the psoas, which is a hip flexor muscle that sits at the front of the upper thigh to the lower back. The contraction of this muscle not only tilts the pelvis anteriorly (ie. Forward and down) which can cause discomfort and pain but this can also increase the compressive forces on the disks.

Another reason besides back pain associated with the sit up is neck strain, this is due to clasping the hands behind the head, but this can result in individuals pulling on their head for leverage and thereby can possibly injure their neck muscles and connective tissues.

Avoiding spine flexion is not necessary for everyone; it really depends on how you spend the rest of your days. If you are like the majority of people out there sitting at a computer all day, you are constantly sitting in a flexed position. So for someone like this the last thing we want them to do is go exercise by sitting or flexing the spine even more. Now if you are an individual who stands all day or spends most of the day on your feet then flexion type exercises may not be so bad, and in fact may be encouraged.

Top 4 tips for getting started


  1. If you suffer from lower back pain or have a herniated disc or any lower back pathology steer clear from sit-ups as it can aggravate your back pain.
  2. Incorporate McGill’s abdominal exercises into your routine, if you have doubt consult an Exercise Physiologist or a qualified exercise professional.
  3. After just 30 minutes of waking, discs lose 54% of the loss of daily disc height and water content and 90% within the first hour. For this reason, spinal flexion exercises should be avoided within at least 1 hour of rising.
  4. Seek advice from an Accredited Exercise Physiologist for alternatives for exercises for the core.


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