Sit Ups are Dangerous? Pilates “Hundreds” Exercises Can Damage Your Pelvic Floor Muscles?

By Marianne Ryan PT, OCS
Clinical Director MRPT Physical Therapy

Think twice before you crunch!

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 eating psyllium husks.  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. Your pelvic floor is shaped a little like a hammock. 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 you do a sit up, an abdominal crunch, or even a Pilates “hundreds” exercise,  the pressure in your abdomen rises. Your pelvic floor should contract strongly and automatically 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 the Pilates “hundreds” can cause your upper abdominals to become over trained and much stronger than your 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 pelvic floor muscles.

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

Now, some of us are more at risk of pelvic floor weakness than others. Some high risk groups include:

  • Women who are pregnant or have ever had a baby
  • Women who have had gynecological surgery, especially hysterectomy
  • Women who are post-menopause, or going through menopause
  • Men who have had prostate surgery
  • Elite athletes (eg. marathon runners, gymnasts, dancers, athletes of high impact sports )

There are other risk factors causing pelvic floor weakness as well; (like chronic cough, being overweight, chronic back pain), which mean that abdominal crunches should really be off the exercise list for most of us. This doesn’t mean you get out of exercising your abdominal muscles altogether!  In the next post you will learn a great way of working out your abdominal muscles while keeping your pelvic floor safe.


35 thoughts on “Sit Ups are Dangerous? Pilates “Hundreds” Exercises Can Damage Your Pelvic Floor Muscles?

  1. John T. Gossett

    When Pilates exercises are done properly you are encouraged to engage Pelvic Floor. We never do a ” crunch “! Pilates uses the whole abdomanal and “core complex ” to stabalize.

    1. Monroe

      I agree. When Pilates exercises are done correctly, the exercise would not be a crunch and the client is working to restore correct muscle firing patterns. In Stott Pilates, we aim for sub maximal PF and TA contraction first, thereby not a big load on them as the author states. Big loads are reserved for global mobilizers.

      1. MRPT Physical Therapy

        Great news Monroe! Do you think doing the hundreds is sub maxmal training for the pelvic floor? Sorry I didn’t address you comment directly, please scroll down to see the comment I made to the entire group of comments a few weeks ago. Does my response make sense to you?

  2. Yvonne Maunder Pilates Instructor

    oh no that really sets the cat amongst the pigeons!!!! Thats really bad news for all fitness pros!!!

    1. MRPT Physical Therapy

      Sorry I didn’t address your comment directly Yvonne, please scroll down to see the comment I made to the entire group of comments a few weeks ago. I think it is OK to do a “few” crunches (like 10 in a row) to re-educate the muscle fibers. Just be careful and watch out for muscle fatigue such as bulging of the pelvic floor or abdominals. Preforming several crunches in a row, like the hundreds, does seem to run the risk of fatiguing the pelvic floor and possibly working against tying to develop a cohesive core group of muscles. Does my response make sense to you?

  3. Gail

    It seems to me that we should be placing greater emphasis on strenghtening the pelvic floor muscles, not telling anyone to avoid abdominal crunches or Pilates exercises. All those muscles need to be strong.

    1. MRPT Physical Therapy

      If the pelvic floor is over trained, as you said “all those muscles need to be strong”, you run the rise in developing tight pelvic floor muscles… tight muscles test weak, which I assume is not what you are “going for”?
      Sorry I didn’t address your comment directly Gail, please scroll down to see the comment I made to the entire group of comments a few weeks ago.Does my response make sense to you?

  4. Mark Hanna

    The closest thing I’ve been able to find to an actual reference on the site you’ve linked to is “Research shows…” on their “Pelvic floor safe exercises” page. Even their “Promoting Pelvic Floor Safe Exercises” PDF for fitness professionals seems to be entirely devoid of references. Are you able to provide a link to an actual reference?

      1. Mark Hanna

        As far as I can tell that comment doesn’t include any references either. What I’m hoping you can do is point me towards the research on which the conclusions in this post are based. I can read what you’ve written here, but without data I can’t determine whether or not your conclusions seem to be correct.

  5. Cat

    I was recently at Melbourne Uni studying a subject for my Masters- Exercise for Women.
    I am a Women’s Health Physiotherapist and also a Pilates instructor, having worked in both the studio setting and mat work.

    This was also a contentious topic for myself to. I was confident that with a pelvic floor contraction maintained throughout the crunch or set of abdominals such as the 100’s was safe.
    This can be objectivified with RTUS ( if you have the luxury), palpating the pelvic floor contraction in a clinical setting (invasive but possible if necessary), or by observing RA bulging.

    This was confirmed to me at the course and it was also put into persective. The IAP rise in a crunch is much less than in coughing, sit to stand and a lot of other functional tasks. There is a great paper that has measured IAP in a variety of activities, crunches were quite low.

    O’Dell, K. K., Morse, A. N., Crawford, S. L., & Howard, A. (2007). Vaginal pressure during
    lifting, floor exercises, jogging, and use of hydraulic exercise machines. International Urogynecology Journal and Pelvic Floor Dysfunction, 18(12), 1481-1489.

    I still agree that we should not give these exercises to those with a POP, but otherwise i don’t have a problem.

  6. Amato Machikicho

    This article is incomplete in its annalysis! Comparing the human torso to a toothpaste tube?!! Why overlook (hopefully not deliberate) the breathing pattern you should employ during a crunch i.e exhale on concentric and inhale on eccentric crunch), safe speed for crunches etc.

    1. MRPT Physical Therapy

      Thanks for you comment Amato, I am sorry I didn’t address you comment directly, please scroll down to see the comment I made to the entire group of comments a few weeks ago. I do agree and use breath work with my clients, but it is a question of muscle endurance and “functional muscle training” Does my response make sense to you?

  7. Tori Brown

    Yes, abdominal crunches can be bad for anyone if they are not working with a fully certified Pilates instructor well versed in educating clients about pelvic floor activation and progression. According to a randomized clinical trial comparing pelvic floor muscle training to a Pilates exercise program for improving pelvic muscle strength, conducted by Atlantic Health Division of Urogynecology, 95 Madison Ave Suite 204, Morristown, NJ 07960, “Both the Pilates and PFMT groups [improved pelvic floor strength] , with no difference between groups p = 0.85. PFIQ and PFDI scores improved from baseline but not between groups. see “”

    1. MRPT Physical Therapy

      Hi Tori, sorry I didn’t address you comment directly, please scroll down to see the comment I made to the entire group of comments a few weeks ago. I am not aware of the study you mentioned and would love to see a copy of it. Do you think you can send me a copy of it?
      Does my response make sense to you?

      1. Tori Brown

        It makes sense except that, once again, in Pilates we do not do “crunches”. I don’t know about other instructors, but when we teach the hundreds we specifically focus on maintaining a neutral pelvis and disassociating thoracic flexion from the lumbar spine, as well as maintaining symmetry between the ribs and pelvis throughout. We also emphasize obliques rather than rectus.. All of that along with stabilization of the shoulder girdle and a focus on breath…I find it a totally functional exercise.

        The link to the PF study I noted, is on PUB MED: I don’t have a hard copy. This info was presented at the PMA conference in 2010 by the individuals responsible for conducting the research.

  8. Caroline

    The whole idea of Pilates is that you engage the pelvic floor first – it’s the first principle to teach engagement of the core muscles. An Pilates instructor should not encourage a client to perform the hundred before sure that they are engaging their core muscles correctly. So, to keep with the same analogy, the lid on the toothpaste tube is on BEFORE curling up. If there is a known weakness, then curl ups (along with other exercises that increase that downward pressure on the pelvic floor) should be avoided.

  9. fred Samorodin

    I lowarned, long ago, to avoid double leg raises under 45 degrees to avoid overstretching the broad ligament and precipitating potential uterine anteversion or retroversion with the increased cross-sectional volume of a contracted psoas. Probably applies to crunches as well!

  10. Paula Pettavino

    I agree with John. The problem is that there are many “Pilates” instructors (some trained in a weekend!) who don’t really understand how Pilates is done. I have a wonderful t-shirt that says: “The thing I like about Pilates is that it’s very easy to do—unless you do it right.” If it’s not done right, the problem is not in the movement system but in how it’s being taught–or “learned” from a video.

  11. MRPT Physical Therapy Post author

    Sorry I didn’t participate in these discussions earlier, but I was sidelined by Hurricane Sandy and now warm and cozy in a NYC hotel room. My heart and prayers go out to those who have been much more affected by this storm.

    Thank you for all of your thoughtful comments, and I hope we can all continue to discuss these issues and learn from each other.

    Please understand, that I didn’t mean for this article to be an anti-Pilates statement, I use a lot of other Pilates based exercises in our practice everyday. However, I continue to believe sit-ups can increase IAP and put too much strain on the pelvic floor.

    I am aware of the study “Cat” referred to:” intra-abdominal / vaginal pressure; O’Dell Int Urogyn J 2007: healthy population intra-vaginal pressure measure”
    The study found that the IAP pressure on the pelvic floor of “one crunch” was much less then coughing “one time”:
    Sharp cough or bearing down – 98 / 101 cmH2O (range 49-120)
    Crunch – Holding Breath 23 cmH2O (19-75).
    with exhalation 12cmH20) (8-75) ”
    The study shows that peak pressure may not be the main problem when performing sit ups; the question is might the load duration and endurance of the pelvic floor be more of the issue?”
    This study does not measure exercises that require a large load or prolonged endurance such as performing the “hundreds” or other crunches multiple times. More studies are needed along these lines.

    So, as a Pilates instructor or Physical therapist you can tell your client to “engage the pelvic floor” but how do you measured when it starts to fatigue? When do you know the pelvic floor has reached fatigue and the global muscles start to take over?
    I don’t think even the most devoted women’s health specialist will want the patient to perform these exercises while internally palpating the pelvic floor.

    I would like to quote Christy C. Ciesla, PT, DPT, who belongs to another one of my discussion groups:
    “I would think that sit ups could damage a healthy pelvic floor in any individual just like healthy people who have not had children (even men) can develop a diastasis recti. Breathing can help, but ultimately the muscle fatigues and form is lost to intra-abdominal pressure. This is not only dangerous for organ support, but as the pelvic floor is a prime stabilizer of the pelvis, those affected can develop significant dysfunction in the lumbopelvic and hip joints… Diane Lee is the big pioneer in this area, and she has made countless presentations around the world on this topic (which are, of course, supported by relevant research and cadaver studies). “

    Stuart McGill has done extensive research on this area; repeated in sit-ups cause disc failure in cadaver spines.

    Crunches are not a functional exercise, there are plenty of other functional exercises which are safe for the pelvic floor and will build up core strength / stabilization without creating muscle imbalances.

    Steve Politis, PT, DPT, FAFS, DMT, CKTP, CSCS gave other examples on more functional ways to safely build up pelvic floor strength and pelvic stability.
    “Another approach with which to view the pelvic floor is from the lens of Applied Functional Science.
    Based on understanding anatomy, specifically that the pelvic floor muscles have continuous fascia with hip external rotators like obturator internus, there are a lot of ways to train the pelvic floor, never do a traditional sit-up, or Kegel, and be more functional for the ways we, as humans move and function in the real world. Standing examples are squats and lunges. By using a wide stance squat and internally rotating the feet you eccentrically lengthen, and proprioceptive turn-on the pelvic floor. As you squat down the pelvic floor is further eccentrically lengthened and strengthened. You can position the feet in 27 different symmetrical positions to tweak the pelvic floor, and hundreds more of asymmetrical foot positions to activate the pelvic floor. Adding lunges creates a more dynamic reaction, steps up, squats with one foot on a box, lunges to and from a box, the possibilities are endless. For lower level needs start with a bridge and tweak the foot positions in the same way, each time your talking to the pelvic floor through how you are eccentrically lengthening it.
    Abdominal workouts, well lots of options there too, just remember, they function eccentrically for the most part. Concentric shortening is not what they do in the real world, except for getting out of bed, or if you do MMA.

    Marianne Ryan PT, OCS
    Clinical Director
    Manhattan PT – MRPT Physical Therapy
    6 East 45th Street, NY, NY 10017

  12. Sornam Joanna Sahadevan

    The most important thing we can do for our clients is to select exercises in accordance to their needs. Flexion may be contraindicated for certain populations. What makes one a good instructor is their ability to know how to provide differentiated instructions and not simply teach by rote.

  13. Vanita Gaglani

    Hi I know this is a little bit late but what Marianne states makes perfect logic. The pelvic floor muscles get fatigued and then they are unable to contract optimally resulting in incontinence . Though I specialize in treatment of incontinence in men following prostate surgery, I do occasionally get these female athletes or just females who exercise a lot and they do have severe incontinence, not only urinary but as one digs deeper they have fecal incontinence as well. They also come to me as a last resort and are surprised by how well they do after Physical therapy.

    1. Fred Samorodin

      Although sit-ups are considered part of core muscle toning–toning a muscle from its neutral to its shortened position with a situp does not strengthen the abdomenal wall muscles very functionally even when there is an oblique movement component to a sit-up(crunch) variation! Functionally, I have discovered to benefits of having clients engage all their core muscles functionally in standing and rotating


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