Are you still doing sit ups in the hope of achieving a strong core?

Sit ups are often performed as a core muscle exercise. However research continually shows that they are not effective at building core strength. Old habits die hard and in the fitness industry sit ups, crunches, roll ups, roll downs etc… have been around for as long as people have been exercising. But, this doesn’t mean that they are good or effective!

Core muscles are those which hold your body together, giving it strength by binding around your trunk. They support your spine and strengthening them can significantly reduce back pain. I would include in core muscles those around the shoulder girdle. They have a big impact on posture which, if poor, can cause the shoulders to slump forward and eventually result in pain. Recent research has also added new muscles as essential for core stability, known as gluteals. This complex muscle group lies across your butt and holds your pelvis stable.

So back to sit ups, what happens to your body during the exercise?

Your shoulders round into a position very similar to that seen in the office chair slump, the slouched driving position or the collapse on the sofa rounding. In other words, good posture across the shoulder girdle is completely lost. When this was first performed I don’t suppose we were living a life of sitting and slouching so possibly the postural issues we see today were not as prevalent.

Your spine is curled forward. For some this may feel good and indeed be beneficial but for many the compressional force on the intervertebral discs will aggravate previous injuries such as herniations (slipped disc) or prolapsed discs. Measuring this compressional force is something we’ve only been able to do in recent years, and it is huge when performing a sit up. When I first taught these exercises the fitness industry was oblivious to these potential dangers.

Once you get almost half way up, your hip flexors become the main workers to stabilise and complete the movement, to bring you up to sitting. These are also shortened by a sedentary lifestyle and if not specifically stretched they pull the pelvis out of alignment causing back pain.

This brings us onto the new core muscles, the gluteals. Generally weak (despite years of tums and bums classes!) and difficult to activate, yet essential for good posture and a strong core. In those who perform lots of crunches the hip flexors, hamstrings and rectus femoris (thighs) tend to be strong but these muscles work in a vertical plane. In these people the gluteals are likely not to work at all, yet they provide all the essential diagonal support for the pelvis.

If you are looking for a strong core, the exercises you need are those which use the gluteals and the stabilizing abdominals, not the sit up muscles.

If you’re tempted to go for a ‘6 pack’, remember that it can only be achieved by over developing the muscles so they push out through the fascia, which is there to hold them together. For a female to develop a 6 pack, as well as the muscle development she also needs a BMI well below that recommended for good health.

For effective exercise advice look for an instructor with a good understanding of spinal load during exercise, preferably with a specific low back qualification and an interest in functional fitness and posture.