When I said I would write my next blog post about injury prevention in pregnant running, I didn't know it would be clouded by such a serious occurrence. No, luckily I have not gotten injured yet, but for those of you who don't read Stefanie Schocke's blog (and I hope she doesn't mind I mention this!), she has just learned that she suffered a stress fracture at the inferior pubic ramus at the end of her pregnancy. She has really been an inspiration to me, with how fast she ran pregnant (made a habit of setting PR's) and how she almost made it to the end before any injury set in. But her injury makes me realize how serious, relevant and poorly understood this topic is among pregnant runners.
I also didn't know when I said I'd write this post that the incidence of pelvic/hip/groin injury was so common in pregnant runners )you are, of course, all smart enough to take a poll on my blog with a grain of salt - but it's hard not to find it a little interesting).
You are more likely than not to have your running curtailed by an injury while pregnant. And the most likely injury (67%) is of the pelvis.
And I consider any groin, hip or pelvic injury to be equivalent. They all occur in the above ring and occur by the same basic mechanism: the uneven loosening of/stress on the pelvis.
What I am about to write is simply an amalgamation of what I have learned in medical school and years of reading about running and pregnancy and is not from any particular research, though I quote one study. The only good reason you have to read it is you probably won't be able to find much else written on this topic (if you do, let me know! I want to read it.).
So, let's get started with my interpretation of the biomechanics that predispose to pelvic injury:
1. The belly grows, of course. This changes the body's position while running. Initially I thought if one ran with a backpack that one would balance out "the problem", but this is the opposite of the truth. (yes, this is my very own illustration)
The truth is, the larger the belly grows, the more a woman leans back to compensate. This puts stress on the sacroiliac joint and the back of the pelvis.
2. At the same time, the ligaments loosen in the pelvis in response to the hormone relaxin. This makes good sense for pushing a baby through. But when things loosen, they unfortunately tend to loosen unevenly.
So what to do to protect the pregnant pelvis while running?
First, buy shoes that promote running on the forefoot. This will give you a posture where you are leaning more forward and less stress with be placed on the pelvis and SI joint this way. If you already run with vibrams or barefoot, you really can't do anything more in this department.
I have now taught myself to run in shoes with very minimal cushion with more of a forward-leaning style. My feet and calves have taken a beating. And it was a while before I could run 3 hours straight in these shoes, but yesterday I did 3 1/2 hours and it went well. I will add that running on dirt as opposed to asphalt makes transition to this running style a lot easier.
Second, you need to have balance in the strength of the muslces that support and surround the pelvis. The balance of strength is perhaps equally important to strength itself when preventing uneven loosening of the pelvis. So what do I recommend? Well, if you run, you legs are strong, but you need to strengthen your abs, back, inner and outer thighs, butt and even upper body to balance things out. Remember this is all theory.
My favorite exercises involve the exercise ball and I attend classes where we focus on the entire body and core. It is easy to overdo the abs and forget the inner and outer thighs for example. Balancing acts (which I have perfected while waiting for trains with my backpack on) are great for strengthening our neglected deep core muscles.
Now, the topic that gets everybody's undies in a bundle: weight gain. It seems intuitive that the less weight one adds to the pelvis, the less chance one has of injuring the pelvis. And I think this is generally true that women who gain less tend to be able to run longer while pregnant. It is very simple mechanics of course, though there are always confounding factors involved.
But, but, but, but. And I admit this actually occurred to me in the last week: women who are pregnant are in essence amenorrheic. They don't have the cyclical estrogen and progesterone spikes that keep female bones strong. Not only this (here comes the one study), but increased prolactin levels cause decreased bone mineral density. Black et al. (J Bone Miner Res 2000; 15:557-63) showed an average decrease in bone mineral density in the spine of 3.5% in 10 women over the course of their pregnancies. First of all, it is thus important to get adequate calcium and vitamin D. But another thing that keeps bones strong is a little extra weight. It is therefore, in theory, important to gain ENOUGH weight so our bones don't weaken too much. (just as an aside, I would love to do a study taking serial dexa scans of women to see if there is a correlation between weight gain while pregnant and the development of osteopenia - or fractures for that matter.).
Sorry, was that just total blabber or what?
Running songs of the day:
Safari Disco Club and Que veux-tu/ by Yelle
Also - Amour du sol by Yelle (can't find a video for it)