Want a Flat Tummy? Don’t Do Sit-Ups or Crunches (Part 1)

Sit Up

By Marianne Ryan PT, OCS
Clinical Director MRPT Physical Therapy

Is it your New Year’s resolution to have a nice flat tummy?

Think twice before you crunch!

I bet you didn’t know that sit ups and crunches can damage your pelvic floor muscles which prevents you from getting that flat tummy look.

This blog is part of a 3 part series on how to develop a flat tummy without doing abdominals crunches. We will teach you some safe exercises which will help you get that desired result.

For most of us, abdominal crunches are on life’s list of things we know we really should do, but are not really that much fun – like flossing our teeth or sprinkling flax seeds on everything we eat.  Well, maybe what I am going to tell you will be good news – ABDOMINAL CRUNCHES CAN BE BAD FOR YOU!

The problem is not so much what these types of exercises are doing to your six-pack abdominal muscles, but the effect they are having on your pelvic floor and deep abdominal muscles. These two muscle groups work together to help keep the lower part of your body stable so you can move more efficiently.

Your pelvic floor is shaped like a little hammock connecting the back and front of the pelvis; and it is meant to act like a trampoline. It is composed of a group of muscles whose job it is to support our abdominal contents, maintain bladder and bowel control and support healthy sexual function. When the pelvic floor muscles contract your deep or lower abdominals should contract at the same time, forming the base and front part of your core muscles. 

When you do a sit up or, an abdominal crunch,  the pressure in your abdomen rises. Your pelvic floor should contract strongly and automatically, like a trampoline, to match the increasing pressure.  If you have weakness in your pelvic floor, the increased pressure will hone in on that area, and can worsen the weakness and cause serious problems, including problems with bladder and bowel control, organ prolapse and pain in the pelvis and lower back.

Also, performing sit ups or crunches can cause your upper abdominals to become over trained and much stronger than your lower abdominal and pelvic floor muscles; resulting in muscle imbalances. If this happens, each time you perform a sit up, the upper abdominal wall tightens and causes funnel pressure which presses down on the lower tummy and pelvic floor muscles. So, you run the risk of developing a little pot belly and a droopy pelvic floor.

The pelvic floor and your deep abdominal muscles are not normally trained to withstand the prolonged pressure created by repetitive crunches. It’s an endurance problem. Pelvic floor muscles can fatigue easily and lose its “trampoline like” effect of matching the downward pressure placed on it by the internal organs.tooth_paste

Take a toothpaste tube; make sure it’s fairly full. Now make it do a crunch – go right ahead and bend it in half! The lid represents a strong pelvic floor. Okay, now do it again with the lid off. Get the picture?

This doesn’t mean you get out of exercising your abdominal muscles altogether!

In the next 2 posts you will learn a great way of working out your abdominal muscles while keeping your pelvic floor safe.

Ref: http://www.pelvicfloorfirst.org.au


14 thoughts on “Want a Flat Tummy? Don’t Do Sit-Ups or Crunches (Part 1)

  1. Marianne Ryan PT, OCS

    Thank you for your kind complement Terri. Please feel free to repost or reblog this post. (please remember to give me the credit:-) Also, keep the look out for the next two posts, this part one of a three part series.
    (BTW, I am really excited because I just registered for the Hypopressive Fundamentals course being taught in Toronto in May! So, thanks for getting me into it.)

  2. Becca Rose

    Do you then advise against crunches/situps completely? Or is it a matter of moderation and not depending on them solely? I am interested to read parts 2 and 3!

    1. Marianne Ryan PT, OCS

      The problem is that crunches/sit-ups place too much pressure on the pelvic floor and deep abdominal muscles; and these types of muscle fibers fatigue easily. So, I don’t recommend doing them. I must admit sometimes I have patients perform a few so they can learn how it feels when their abdominals contract, but I don’t give them out as home exercises.

      1. Simon Trangmar

        Dear Marianne

        Greetings from Adelaide, South Australia
        Found your article very useful, have printed it out and will be giving it to a few girls in my classes (I will ensure I leave your details at the bottom of the articles). Gym junkies who just can’t seem to get flat lower stomachs – funny that! 🙂

        I am also anti ab crunch and was surprised to read that crunches can actually DAMAGE a P/F – wow, didn’t know that. I had just assumed crunches worked six pack (ineffectively at that) and didn’t do much for lower tummy.

        Despite my best efforts, I often find guys who want bulging washboards over flat lower stomachs so for them, I have them lying backwards over a fitball and doing very slow gentle femur arcs. In that position (ie the polar opposite of flat back), the work seems to be largely borne by their upper abs but at least there’s no jerkiness to injure lower spine. Also, done really slowly tends not to bulk the six pack overly and, of course, the stabalisation required on the fitball seems to magnify the move (and work TAs a little for them)

        Oh male vanity.

        Regards – Simon

  3. Julia

    I wish I’d read this article 30 years ago. I have a prolapsed uterus and cystocoele and I would wish those on anyone. I blame sit-ups. I could even feel something wrong happening as I was doing the situps all those years ago. If I knew what they’d lead to, I’d never have done a single one.


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