Recent News and Events

by Emmi Aguillard, PT, DPT, FAFS

Posted in Blog.

July 7th, 2021

Stress Fractures and the Female Runner: 5 Factors Things to Consider

Female runners are far too often plagued with bony stress injuries. The question always comes up: Why does this keep happening? As a physical therapist, this is something I see far too often in the clinic, and has lead me to have many conversations with doctors, nutritionists, countless patients, coaches, and other PTs to try to find the answer. 

Specifically, when the stress injury involves the pelvis, it is important to take a multi-faceted approach, because this bone is much denser and stronger than the shin. All bony injuries are NOT created equally – in fact, it is usually the interplay of several factors that can cause them to occur. Female pelvic stress fractures often happen as a result of a perfect storm: nutrition, hormones, biomechanics, training, and stress. In this blog, we will take a deeper dive at understanding the connection between these factors and your body, and what you can do to stay healthy, recover better, and avoid injury.


It is CRITICAL for runners to consume adequate protein post-run. When we run, our muscles and bones sustain tiny microtears and microfractures. This is what causes the soreness that we feel. But our body does an amazing job of rebuilding during the recovery period, laying down more muscle and bone to repair what was damaged, making us stronger than we were before. This is how we adapt to the repetitive stress and load that occurs during training (and why the recovery period is so critical to avoid injury). The body needs protein for this process to happen, and for women, our window to reap the maximum benefits of consuming protein is only about 20 minutes post-workout! Men typically have a much wider window, up to about 90 minutes. Your body takes the protein you ingest and breaks it down into amino acids, which are the building blocks for new, stronger muscles. It’s imperative that we intake protein during this  critical window, because we metabolize it most efficiently at this time. 

I know this can be so challenging in the [normal] world we live in – we go out for our run – run home, shower, head to work, and finally sit down to our yogurt and granola once we reach our desk, but that 20 minute window is imperative for female athletes to pay attention to! 

→ short on time? I’ll grab a few slices of deli turkey, a glass of milk, or a protein bar! You can also add a scoop of protein powder to your smoothie (just make sure to do it within 20 minutes of ending your run)! 


The female hormones – specifically estrogen – play a critical role in bone health. Think of estrogen as a protector of your bone. Your body needs an adequate supply of estrogen in order to PREVENT bone resorption. Bone resorption is the breakdown of calcium from our bones in order to release it into our bloodstream – increasing your risk for osteopenia or osteoporosis. It’s CRITICAL for women to have adequate levels of estrogen and calcium for our bodies to properly recover from and adapt to the increased loading and pounding of running. How could this be affecting you? If you’ve been on a low-estrogen birth control for a prolonged period of time, you could actually be suppressing your body’s natural supply of estrogen which can lead to a weakening of the bones and increasing your risk for a bone injury. This is a great conversation to have with your gynecologist or endocrinologist. 


The way we land plays a HUGE role in the load that is going into our joints. I’m going to break it down a little bit technical here. When our foot strikes the ground (the loading phase of gait) the femur [thigh bone] should translate backwards into the pelvis – this force stretches out (lengthens) or “loads” the glute – like you are pulling back a sling-shot or rubber band. Then, this loaded glute slings us forward (unloading phase), propelling us into the flight phase of running.

If you have tightness in your hip flexors or stiffness in the pelvis, the femur may load the hip either too far forward or too much out to the side. Too much lateral loading leads to issues like IT band syndrome, but if the femur is loading into the hip too far forward, then there is more stress directed to the bone due to poor loading of the muscles, which can put a runner more at risk for stress fracture. Because of the shape of the female hip compared to the male (wider, more ligamentous laxity, designed for child birth), we are more at risk for stress-related injuries at the hip than men. 


It’s so important to follow a training plan that is targeted towards YOU as an individual, and not get swept up by what others around you are doing. Important things to consider are the number of years that you have been running, what types of training surfaces are available, how much sleep you are getting, and what other outside stressors that you have going on in your life. 

Let’s take a quick look at the marathon. There is a reason why most elite marathoners are in their 30s. Most elites began running at a young age (middle or high school), but have accumulated YEARS of adaptation of their bodies and bones to the high mileage before attempting a marathon training cycle – think 15 years of covering the mile, 5k, and 10k distance before attempting the marathon. Yet, our running culture continues to obsess over the marathon. If you continuously find that you just can’t make it through a training cycle and stay healthy – let’s get back to the basics! Start with the mile. Throw in some interval training and try for a 5k PR. Do you feel solid in the 5k? Maybe a 10k! Build confidence in the half. These stepping stones are so important in becoming a smart, healthy, and well-adapted long term runner. Interns don’t apply to be the next CEO of the company they are working for, and Kipchoge didn’t become a marathoner overnight. As much as we all hate it, don’t skip the fundamentals!! 


The final factor that can’t be ignored is external stress from other areas of life. While a lot of time, running is seen as a stress reliever, it too is an added stressor on your body’s adrenal system, contributing to spike in cortisol levels. Research supports a correlation between increased cortisol levels and decreased bone density in pre-menopausal women, because of the negative effect that an increase in cortisol can have on your body’s production of estrogen. If you are juggling training on top of stress from work, family and personal life – something has to give before your body – literally – cracks. 


Oftentimes, and ESPECIALLY at the pelvis, it isn’t simply one of these categories but a combination of factors, that is causing an injury to occur. To get to the root of the problem and to prevent recurring injury, it’s so important to have an understanding of the interconnection of these different factors, which often takes a multidisciplinary approach to fully understand. If you’ve been plagued by chronic stress injury, I would strongly encourage having conversations with your physical therapist, nutritionist, gynecologist or endocrinologist, and a female-sports medicine doctor to get to the root cause of what’s going on! 

Questions? Reach out to one of our pelvic health PT specialists –

Thank you! Your subscription has been confirmed. You'll hear from us soon.
Subscribe to our newsletter: