The Period Posts: How Your Period Affects Injury

Hazard! High levels of estrogen in the area!

Last year, Clove wrote a couple of informative posts (see here and here) about the nuts and bolts of the menstrual cycle and how it can affect your running.  Today I’m adding to this conversation by asking the question: can your menstrual cycle cause or worsen injuries?

A few days ago, cooling down after an innocuous 4-mile run, I felt the niggly nagging of my left posterior tibial tendon (my version of the Achilles heel) telling me it wasn’t happy.  Now if you’ve ever read my training logs you know I have struggled with this injury for quite some time, but over the past few months it has been feeling much better and I’ve been able to string together a reasonably healthy block of training.  However, it does still bother me intermittently and I’m always trying to figure out the triggers.  So when I got home I looked through my training log to check out the previous few days and compare them to what I was doing when last it bothered me.  Sure enough, just about a month earlier I had a few days of unprovoked soreness…..and wait a second, a few days of soreness just about a month before that…..and again a month before that.  Coinciding each time with the few days before getting my period.  Which made me wonder, was I falling victim to some strange variant of PMS?

When I turned to the medical literature to try to figure this out, I found a fairly extensive body of work devoted to studying the role of sex hormones (which circulate in high levels around the time you get your period) in soft tissue injuries in women.  All the studies I looked at made reference to the fact that women suffer more tendon and ligament injuries than men, and the hormone estrogen, in particular, has been implicated as a potential contributor to this.  In one study, higher levels of estrogen interfered with the ability of women’s knee tendons to regenerate after exercise. This is because the body can’t make new collagen well when estrogen levels are high, and collagen is one of the primary ingredients in our soft tissues.  Another study demonstrated a similar finding in women on oral contraceptive pills (OCPs, most of which contain the two female sex hormones estrogen and progesterone); women who took OCPs did not regenerate collagen as well as those who did not.

The Menstrual Cycle

Several studies (see here and here) even specifically examined how the hormonal fluctuations of your period cycle can affect the ability of your tendons to recover and heal after bouts of exercise.  Estrogen is very high during the “luteal phase” of the menstrual cycle, which is the last week before you actually get your period, so the authors of these studies hypothesized that women’s tendons would not heal as well during this time of their cycle.  However, this did not turn out to be the case; like the prior studies I cited, in these two studies women’s tendons did not recover from exercise as well as men’s, but this was true regardless of what stage of the menstrual cycle a given woman was currently in when she was studied.

Of particular interest to me was one other study that actually checked to see if there are estrogen receptors in posterior tibial tendon tissue (there are in ACL tissue), and whether there are increased numbers of these receptors in tissue from male and female patients with posterior tibial tendinitis.  If so, this would suggest that estrogen is more active in diseased tissue in this condition. Lo and behold, there are estrogen receptors expressed there, but the numbers are no different in men versus women, or in those with diseased tendons versus those with healthy tendons.

So can I blame my monthly posterior tibial tendinitis flares on PMS?  I certainly would like to – it beats blaming it on my running!

Have you ever noticed any funky flares of soft tissue injuries around the time of your period?  How else has your period negatively affected your training?

Enhanced by Zemanta

Mom of three kiddos and a black lab, running enthusiast, sports-med-doctor-in-training. I love the science and sport of running and all things related.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.


  1. Hooray for science! I’m a sucker for good research–thanks for the reading material 🙂 Because of the way my body reacts to the birth control I’m on, I haven’t had a period in nearly 2 years (my doctor says this is ok for me! Promise!) Before I got on BC, however, I definitely remember experiencing extra running-related soreness around that time of the month, so this all makes sense. Bodies are crazy!!

    1. I know, isn’t science the best? So interesting that you’ve had that experience too – thanks for providing another piece of data in support of my theory!

  2. I have asked this exact question (yes, exact. PTT being my achilles heel as well!), and was fascinated by the research you presented here. I’ve noticed the same pattern with regards to tendon pain/ injury, and I can trace the start of every issue/injury not to a specific time in my training cycle, but to the monthly one. Surprised the research doesn’t support the link as our anecdotal experience certainly does!

    1. I was hopeful for more of a link too, but it’s possible there are indirect effects of hormonal fluctuations, like salt balance and fluid retention, for example, which contribute but were not specifically looked at in the studies I found.

  3. Interesting! I’ve never noticed aches along with my cycles, but one of the first symptoms of my pregnancy was an Achilles issue. which I’m guessing had something to do with the hormones going crazy.

  4. I’ve always had sore hammies, particularly my left one as well as back pain, more so than any cramps. I noticed my legs felt like jello at the track tonight. I still hit my times but chalked up the discomfort to PMS. Thanks for providing such insightful studies!

  5. absolutely! During the 3-4 days before my period, little aches become big ones, mystery aches spring from nowhere, and I am always convinced I have a stress fracture. And then it all goes away.