Bone injuries suck. There’s no quicker way to grind your season and training to a halt than hearing your doc murmur the “s” word: stress fracture. For most women, the diagnosis is often accompanied with a test to determine bone density. For men the answer is typically along the lines of rest for six weeks then start back slow.
For those referred on for bone density testing, it’s not uncommon for the test to come back negative. The question then becomes “why?” Why, if your bones are deemed healthy, do they break?
Knowing that our bones grow stronger through a response to load (Wolff’s Law), we would expect that the running would actually yield bones. High, repetitive impact should forge steel-like bones through adaptation.
A study comparing bone health in female long distance runners and sedentary controls found that, although runners were more fit, the runners had identical bone density measurements compared to controls.1 Another study in 1998 found the same results: runners are more fit but measure similar bone density when compared to sedentary controls.2
Well that stinks. Ideally you would like stronger bones than those who don’t run, right? It’s worth noting that both the runners and sedentary controls had rather normal bone density results. It’s just stating that runners don’t have stronger bones that those who don’t run.
The question returns: if my bones are healthy, why are they breaking?
A five year study following female master runners found no significant change in bone density over time.3 This is great news! Running can keep your bones strong as we age.; however, the “s” word arises when we deviate from the typical running plane.
The answer comes down to strength. Ugh. Not another “you should be incorporate strength training” article. Well, I’m sorry. When we begin connecting the dots in the “why do my bones break” mystery, it’s clear that poor training and weakness are the result.
Milner et al. found that the occurrence of stress fractures in female runners was related to greater and faster initial loading of the lower extremity.4 In less fancy words—you’re not shock absorbing.
What slows initial loading of your leg? Well, muscles of course. Muscle fatigue and weakness will cause normal bone to load faster with less control… eventually straining the bone until it breaks.
I get it. It’s tough to incorporate strength training into your training plan. The system (and thinking) is ass backwards. Think about it… when someone gets injured what do they do? They seek exercises to rectify the problem. Have you ever thought about protecting yourself before you’re injured?
It comes down to supplementing your running. If you’re not on the prevention wagon it’s time to rethink the way you train. “I don’t have time isn’t really an excuse.” It’s only a matter of time before the wheels fall off.
This is particularly true for women and even more so for those who are post-menopause. Fluctuating estrogen levels can put women at a huge disadvantage to avoiding a stress fracture. Paired with fluctuating hormones, fatigue and weakness can easily send you to the “s” word.
My typical recommendation is to work strength in twice a week during lower mileage or base building phases. Obviously time can be the limiting factor. As your mileage increases do your best to stay true to twice a week; however, dropping to once a week is better than nothing at all.
If you’re looking for quick, effective strength workouts that are specifically designed for runners, stream my online runner-specific strength workouts. You can perform each workout from work, home, or on the road (aka you have no excuses!): sign up by clicking here.
1. Kirk, S., C. Sharp, N. Elbaum, et al. Effect of long distance running on bone mass in women. J. Bone Miner. Res. 4:515–522, 1989.
2. Ryan, A. S., and Elahi, D.. Loss of bone mineral density in women athletes during aging. Calcif. Tissue Int. 63:287–292, 1998.
3. Hawkins, S., Schroeder, E., Dreyer, H. Five-Year Maintenance of Bone Mineral Density in Women Master Runners. Med Sci Sports Exerc. 35(1): 137-144, 2003.
4. Milner, C.E., Davis, I.S., Hamill, J., 2005. Is dynamic hip and knee alignment associated with tibial stress fracture in female distance runners? Medicine and Science in Sports and Exercise 37, S346.