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Crunches: are they Bad?

What puts more pressure on the pelvic floor - an Abdominal Crunch or Standing up from a chair?

Did you know that an abdominal crunch, lifting a new born child above your head, climbing stairs and walking on a treadmill (4-5km per hr.) are all less pressure on the pelvic floor than simply standing up from a chair?

And how many new mothers have been told NOT to do crunches or avoid excessive lifting of their toddler/child because of pelvic floor issues, but continue to go from sitting to standing at home….

First, let's decide what makes an exercise “riskier” for the pelvic floor or puts undue pressure on a fragile postnatal core. The table below shows the different pressure transmissions in the pelvis and in the abdomen during different exercises. The lower the pressure values, the less "risky" the exercise is to the pelvic floor or abdominals.

Exercise Intra-vaginal Pressure Intra-Abdominal Pressure

Lying down at rest 5 -

Lying down on your back &

doing weights 10 -

Crunches - breathing 12 68

Crunches – holding

breath 24 68

Standing at rest 24 39

Sitting at rest 25 -

Stair climbing - 70

Walking 26 76

Stand from chair - 79

Supine low bicycle 32 -

Seated arm machine 37 -

Seated leg machine 44 -

Seated abdominal machine 54 -

Free weights from floor (10kg) >45 122

Squatting or lunging - -

Jogging 64 100

Jumping jacks - 127

Laughing 86 -

Forceful cough 98 136

what are the take home points?

  • Always breathe through the exercise – holding your breath can double the pressure in your pelvis.

  • There's no real difference between sitting weights training and standing weights training in terms of the effects on the pelvic floor but many benefits to training your core and activating your stabilizing muscles during standing exercise.

  • Crunches and sit-ups are always given a bad rep with regard to pressures on the body and the pelvic floor. They actually produce less pressure than any other seated or standing exercise, and even less pressure than just standing upright! They might not be the best exercise if you have a neck or back injury or an abdominal separation though and are often completed incorrectly so why do them are what are better exercises.

Abdominal muscles connect our rib cage to our pelvis, keeping our spine healthy and our midsection strong enough to carry us through the day. Strengthening your core can help improve your posture and better prepare you to tackle all kinds of everyday tasks — and, of course, it can also help you develop a trimmer, firmer waistline and a “six pack”. After childbirth our Abdominals feel stretched and no longer connected to our bodies in the way they once were.

Unfortunately, the basic crunches and sit-ups we've been taught are not actually the most efficient or healthiest ways to build a strong core. Worse, they may cause serious damage to your back and neck if you do them wrong or make abdominal separation worse or even cause a hernia (but this can simple be from coughing!)

"Six-pack" abs have developed something of an unattainable appeal, but the truth is that everyone has abs though at times it may not feel like it, especially in the early postnatal stages. These muscles are grouped into three areas of our midsection.

There are the surface "six-pack" muscles (rectus abdominis), the deep core stabilizers below them (transverse abdominis), and the side muscles (obliques).

The problem is that many core exercises, when done wrong, don't target these areas of the body very well and just add increased pressure to our internal organs and pelvic floor. Such as straight-leg sit-ups for an example. Many just feel the pressure on the lower back as opposed to recruiting the correct abs to complete the move correctly.


How to train your abdominals correctly is to mimic the way you move in life. After all the true job of our core muscles, is to stop movement and stabilize the spine, protecting our spinal cord and letting us stand and bend. There's also evidence that regular strength training with weights is great for your core. A great simple exercise to work the stabilizing muscles is a move called "suitcase carriers." You can use a heavy bag instead of dumbbells or kettle bells and simply walk around keeping correct form.

Functional movements that apply to real life are obviously the most important to do. Think of the key motherhood movements we complete daily: squats lunges, arm reaches, sitting to standing, working in different movement planes. We very rarely keep to a perfect squat or lunge except in exercise classes. Just moving a foot off center or at a different angle works the muscles differently. Breathing is also important and always exhale on the effort of a movement. So, in a squat, lunge or push up the exhale (out breath) comes at the upward moment.

So, in conclusion, to work our core do we need to do endless crunches/ab bicycles/sit ups? The answer is no, unless in your life you complete lots of movements lying down. Standing up, complete squats/standing knee raises and arm raises to work your core safely in the early postnatal stages, then slowly add in more weight or range of movement as you gain strength.

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