“Do you have any kids?” A question I frequently ask my female patients during my past medical history. I’m not even looking for recently, either. As we’ll see in the research below, the effects of bearing a child are measurable up to 12 months (and that’s only because they stopped the study). It’s an often overlooked question by exercise professional that provides great anatomical insight. It goes without saying (although I’ll say it now anyway) that the female body takes a beating while carrying a child from conception to birth. Unfortunately, we can add postpartum months (or even years) to the already completed nine months. The combination of a growing baby and fluctuating hormones, particularly those at birth, can extremely compromise proximal stability.
With a six month incidence rate of 27% and nine month prevalence of 49%, back pain is overwhelmingly common in expecting mothers.1 A growing baby causes observable changes in posture and muscle length, particularly of the abdominals. The constant stretch held throughout pregnancy can thin, weaken, and even tear your rectus abdominis (traditionally thought of as the “six pack”). Such a constant stretch, one so persistent and strong that it can actually tear the muscle, greatly affects strength. Research conducted in 2011 found that tears in the abdominal wall, known as diastasis recti, as well as abdominal muscle function improved since birth, but had not returned to normal values when measured six months postpartum.2 Another study that was conducted for the first year postpartum found similar results. The abdominal wall was healing, but not healed. Subjects had a thinner, wider rectus abdominis, while the diastasis recti continued to shrink.3
Looking at the above image it’s fairly easy to see the changes in muscle length. Luckily our muscles are fairly elastic and allow for such a stretch; however, the prolonged lengthening of the musculature compromises both strength and stability well beyond delivery.
The weakening and thinning of the abdominal beyond delivery can certainly create some bumps in the road for running moms looking to get back on the horse. As we’ve seen in previous articles, diminished core strength can cause an array of lower body injury (read our previous article on core strength here). The key here is to be patient and to begin a core and pelvic floor strengthening program when deemed safe. Your ability to begin a core strength program will likely depend on mode of delivery. The increased recovery time associated with a caesarian section will have you pumping your brakes for a little bit longer.
I’m ready… where to start?
I often recommend spending time will more gentle, easier modes of aerobic exercise. Aerobic exercise will be fine, but you’ll want to limit impact forces. I know. You’re chomping at the bit to hit the roads again but be patient. Remember, you’re proximal stability (hips and spine) is lost. Running too early will likely leave you sidelined for a few weeks. The first four weeks of exercise (note: this is the first four weeks when you’re ready to begin) should include walking, cycling, and progressive strength training. I highly recommend nixing running as your “get my pre-baby body back ASAP” choice of exercise. Emphasis for your progressive strength program should be at the hips, pelvic floor, and abdominals. Once you begin your return to the roads you’ll want to spend a minimum of four weeks of easy running, working your way back to typical mileage. Tack on another four weeks of occasional higher intensity runs and you’ll likely be ready to begin racing. Yes, that’s weeks of strength training, a minimum of four weeks of ‘getting back into the swing of things’ running, and another four weeks of higher intensity running before you’ll begin planning your race calendar.
Again, this isn’t only for the mothers who recently carried a child. The results are likely measured beyond 12 months, but it happens to be the last data point for the researchers above. I’m sure most moms will attest that the effects certainly span longer than a year. So whether you’re a new mom, adding to your family, or beyond adding, improving spine stability is a must… not only for running, but for life.
1. Ostgaard H, Andersson G, Karlsson K. Prevalence of Back Pain in Pregnancy. Spine. 1991 May;16(5):549-52.
2. Coldron Y, Stokes M, Newham D, Cook K. Postpartum characteristics of rectus abdominis on ultrasound imaging. Man Ther. 2008 May;13(2):112-21.
3. Lih-Jiun Liaw, Miao-Ju Hsu, Chien-Fen Liao, Mei-Fang Liu, Ar-Tyan Hsu. J Orthop Sports Phys Ther. 2011;41(6):435-443