Low back, pelvic, and hip stability are so important. I’ll relate them back to a concept of “proximal stability.” I’ve touted the benefits of core strength before–both articles can be found here and here. I’m not looking to beat a dead horse, but simply expand upon these concepts with a couple simple home tests that can help you understand what you’re bringing to the table. Loss of proximal stability can happen for various reasons: pregnancy, hormones, lifestyle (sitting), or maybe even complete neglect in your strength program (or lack there of). And although I’m going to relate this all back to postpartum moms, this article and the tests apply to all runners. Research notes measurable weakness 12 months postpartum. Again, this weakness may even last longer… the study simply ended at 12 months. Also, there’s little evidence of how multiple pregnancies fare for moms. I presume through clinical observation that the issue is only compounded both in the amount and duration of weakness.
As previously described both here and here, moms take the blunt force of losing proximal stability. Not only do expanding abdominals muscles lose strength, but hormones released during pregnancy and delivery compromise another source of stability: ligamentous support. A properly named hormone, Relaxin, is released in the late stages of pregnancy to soften the pubic symphysis and increase ligamentous laxity surrounding the pelvis. This joint laxity paired with the noted strength deficits through the abdominal wall significantly compromise any proximal postpartum stability. Before you start talking trash to relaxin try to remember that it’s necessary for delivery and safe passage of your little one.
Mothers who undergo cesarean sections (c-sections) are not immune to the destabilizing release of relaxin; however, a c-section has been found to limit the loss of pelvic floor strength postpartum when compared to that of a vaginal birth.1 The body will always assume a vaginal birth, which is why the relaxin is unavoidable. The fact that the abdominal wall is cut during a c-section may, in fact, provide increasing and long term instability at the lumbar spine (this is a presumption).
Identification is half the battle. You’ll want to investigate your overall strength and stability through the spine, hips, and pelvis. A few simple movements can give you a small glimpse into stability. These two movements are always included in a patient exam, whether it’s a man or woman. Although there are far more extensive exam components, these two simple tests can give you a quick glimpse and better understanding of your core, hip, and pelvis stability.
The goal is to apply unilateral force through the spine and pelvis. The momvement requires your muscles to stabilize and prevent movement. Since ligamentous laxity is not thought to resolve to preexisting levels, stability of your spine, pelvis, and hips falls to your muscles. Before attempting these movements there’s an assumption that you’re capable of performing each properly for a full minute. Unable? You know it’s time to start improving proximal stability.
Luckily, we can all run with underlying weakness; however, eventually the tipping point is reached–you’ll need to pay the piper. Restoring core strength and stability will be a necessity to overcome recurring injury. Single sided weakness is not uncommon, either. You may find that hovering one foot versus the other yields different results. No matter the response the answer is the same. Begin improving core strength and stability.
Y.B. Baytur, A. Deveci, Y. Uyar, H.T. Ozcakir, S. Kizilkaya, H. Caglar, Mode of delivery and pelvic floor muscle strength and sexual function after childbirth, International Journal of Gynecology & Obstetrics, Volume 88, Issue 3, March 2005, Pages 276-280.