In the clinic, we have recently seen more runners dealing with bone stress injuries. In many cases, this is not because running is inherently problematic, or because strength training is a poor addition. More often, it reflects a mismatch between training load and the body’s ability to recover and adapt. Bone stress injuries occur when repetitive loading creates microdamage in bone faster than it can be repaired and remodelled (Warden et al., 2021).
More people are aiming higher
There has been a clear rise in interest in fun runs, half marathons, and marathons, with many people taking on longer-distance goals for the first time. At the same time, more people are combining this with regular gym-based or class-based strength training. For many, this is a really positive shift. People are motivated, engaged, and aiming high with their health and performance. The challenge is that cardiovascular fitness can improve faster than bone and other tissues adapt. Someone may feel fitter and more capable from a heart and lungs perspective, while their musculoskeletal system is still catching up to the repeated loading demands of training (Warden et al., 2021).
Where social change, cultural change, and physiology meet
What we are seeing is really a collision of social change, cultural change, and physiology. Socially, more people are participating in organised endurance events and identifying with goals that once felt reserved for more serious athletes. Culturally, the rise of the “hybrid athlete” has created a training identity built around doing more, running further, lifting regularly, and often looking athletic while doing it. Physiologically, though, the body still follows the same rules it always has. Bone adapts more slowly than fitness improves, and it needs progressive loading, adequate recovery, and enough energy availability to remodel well (Hamstra-Wright et al., 2021; Mountjoy et al., 2023; Warden et al., 2021).
There is nothing inherently wrong with this style of training. In fact, for many people it is enjoyable, meaningful, and a great way to stay healthy. The issue is that the demands of this type of training are often underestimated. When higher running volumes are layered on top of strength classes, conditioning, plyometrics, work stress, and everyday life, the cumulative load can rise quickly. If recovery, sleep, and fuelling do not rise with it, the body can gradually fall behind (Hamstra-Wright et al., 2021).
The role of energy availability
A key piece of this is energy availability. High training loads require adequate energy intake to support performance, recovery, and bone remodelling. If someone is training frequently across multiple modalities while unintentionally under-fuelling, their ability to recover and adapt can be compromised. This is one of the important reasons bone stress injury risk can rise in both female and male athletes when load is high and recovery resources are not keeping pace (Mountjoy et al., 2023).
Why early recognition matters
One of the challenges with bone stress injuries is that they often build gradually rather than appearing out of nowhere. They are usually the result of repeated loading over time without enough capacity to absorb, recover from, and adapt to that load. Early symptoms matter, especially focal pain that worsens with impact, lingers after exercise, or becomes more noticeable with hopping or running (Warden et al., 2021).
Key takeaways
- Bone stress injuries are often the result of load building faster than the body can recover and remodel.
- Running fitness can improve faster than bone and other tissues adapt.
- Combining running with frequent class-based strength training can work well, but total weekly load matters.
- Under-fuelling and under-recovery can reduce the body’s ability to adapt to training.
- The growing popularity of longer-distance events and hybrid training is a positive trend, but it requires a better understanding of exercise physiology, recovery, and tissue adaptation.
- Early focal bone pain should be taken seriously and assessed early.
Final thought
As one of our clients, Matt Sostarik, put it: “The marathon is the new Couch to 5K.”
There is a lot to like about that idea. People are striving for more, aiming higher, and embracing challenges that can be incredibly rewarding. We love that. But these goals need to be pursued with a clear understanding of how they affect the body, how to prepare properly, and how to minimise the chance of injury along the way.
If this sounds like you
Focal bone pain that lingers after a run, worsens with impact, or shows up more with hopping than walking is worth getting assessed early rather than waiting it out. The earlier we catch a bone stress injury on the loading continuum, the simpler the fix.
If that’s ringing any bells, book in with us and we’ll help you figure out what’s actually going on, and how to keep training toward that marathon without your body paying for it.