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Exercise & Pregnancy

Michelle Bridges, the 45 year old celebrity personal trainer on the Biggest Loser, has been under fire recently for her choice of exercise during her pregnancy. She is due to give birth in December, and would currently be in her third trimester. She was recently photographed doing a workout on a beach, involving doing abdominal crunches (or curl-ups) while lying over a gym ball.

Michelle has copped a lot of criticism from many people, including Women’s Health Physiotherapists, who have warned about the possible implications for her own body, as well as the poor example she is setting to other pregnant women, who may see her as a role model and aim to follow her example.

So what is the issue? Is this exercise inappropriate for pregnant women, and if so, why?

Firstly let’s look at exercise guidelines for pregnancy. Daily exercise, including aerobic and strength training, is recommended for pregnant women as long as there are no medical complications that would specifically exclude exercise.

While for many pregnant women, their daily exercise may be at a lower intensity than Michelle Bridges’ regime, we also need to take into account each woman’s starting fitness and activity level. If like her, your body is accustomed to working regularly at a higher intensity pre-pregnancy, you may be able to continue doing higher level aerobic and strength training during pregnancy, under the guidance of your medical practitioner or physio, and as long as you and your developing baby are not experiencing adverse symptoms.

In many ways, Michelle Bridges is setting a good example by continuing to exercise throughout her pregnancy, as unfortunately this is a time when many women cease regular exercise. The important thing is that you consult a health provider who understands about pregnancy exercise guidelines before starting, or continuing, with exercise during pregnancy.

So as Michelle Bridges was already exercising at a higher intensity, the debate isn’t over that, but over the exercises she was doing. Doing crunches on a gym ball is particularly controversial because the guidelines for exercise during pregnancy specifically recommend against a number of the components of this exercise past 16 weeks of pregnancy.

1. The first reason this is discouraged is the position of the exercise: supine (or lying on your back).

In supine, the weight of the uterus may obstruct blood flow to and from the heart to the uterus itself and the lower part of the woman’s body. This can result in postural hypotension, which when mild just makes you feel dizzy and nauseous, but could potentially detrimentally effect the foetal blood supply.

Although Michelle was lying over a ball, she is still supine, and therefore not following correct pregnancy exercise guidelines. While she and her baby may well be fine, it just shows although she is a personal trainer, she is not necessarily aware of the guidelines for exercising in pregnancy.

2. The second point of concern is that abdominal crunches are generally not recommended for pregnant women in the second and third trimester, as it is questionable as to whether that kind of load on the abdominal muscles is appropriate.

As the foetus grows, the abdominal muscles become thinner, wider, and have reduced strength and endurance. So can they cope with crunches?

3. The third issue is the risk of separation of the rectus muscles along their connection centrally through the linea alba, and‘doming’ of the abdominal wall.

If you look at the picture of Michelle Bridges,you can see there is a bulging (doming) along the mid-line of her abdomen between her ribs and navel – no, it’s not just the baby!

This is the main point of concern that has many people jumping up and down. This separation of the rectus muscles along the linea alba is called a rectus diastasis, which has been linked to pelvic and low back pain and may also impact on pelvic floor muscle function.

Traditionally women have been told that curl-up exercises would make a rectus diastasis worse. However, a recent study has shown curl-ups actually reduce the separation in both pregnant and postnatal women, whereas drawing-in exercises(activating the deep abdominal layer) may slightly widen it.

And possibly the depth of the diastasis and herniation (doming) of inner abdominal contents through this separation are more concerning than the width.

Certainly postnatally, many suggest a controlled curl-up can be a useful exercise for restoring abdominal muscle tone, improving function and narrowing the rectus distasis.

In pregnancy though, when the muscles are still stretched,we just don’t know. Either pre or postnatally, an uncontrolled curl-up with abdominal doming and pelvic floor pressure may do more harm than good.

So if you are pregnant and looking for exercise advice, make sure you talk with someone who specifically knows about exercise guidelines for pregnant and post-partum women. Many Women’s Health Physios are able to offer good advice on this.

To find out more or book an appointment with one of our Physiotherapists, call us on 8373 5655.

1 Gilleard WL and Brown JMM (1996): Structure and function ofthe abdominal muscles in primigravida during pregnancy and the immediatepost-birth period. Physical Therapy 76(7): 750-762.

2 Lee DG et al (2008): Stability, continence and breathing:The role of fascia following pregnancy and delivery. Journal of bodywork and movement therapies 12: 333-348.

3 Mota PGF et al (2015): Prevalence and risk factors ofdiastasis recti abdominis from late pregnancy to 6 months postpartum, andrelationship with lumbo-pelvic pain. ManualTherapy 20: 200-205.

4 Mota PGF et al (2015): The immediate effects on inter-rectus distance of abdominalcrunch and drawing-in exercises during pregnancy and the postpartum period. Journal of Orthopaedic and Sports PhysicalTherapy 45 (10): 781-788.

5 Royal College of Obstetricians and Gynaecologists (2006): Exercise inpregnancy. Statement no 4.The American College of Obstetricians and Gynecologists(2012): Exercise during pregnancy.



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