Bones Are Always Changing
Bones are like a perpetual construction site – there's always remodeling going on. Old or damaged bone gets cleared out and new bone gets laid down.
Your skeleton gets the instructions to build up or break down from the types of stressors on your bone.
That includes things like training load and nutrition (we'll get to those in a bit).
In healthy skeletons, bone is able to adapt and can repair as needed.
Like so many other tissues in your body, it will get stronger if given enough time and energy.
For example, in well-trained pitchers, bones are almost twice as strong in their throwing arm. If the other arm had to deal with the same force, it would break!
So What’s The Problem Then?
Problems arise when bones don’t have enough time or energy to recover and adapt.
When this happens, the scale shifts towards breakdown, and bones begin to get weaker.
If this process continues, you’ll get a stress reaction in the bone. Swelling occurs in and around the injured bone, and the bone gets more sensitive to stress.
If nothing changes, the stress reaction will progress to a stress fracture.
Stress fractures need especially tender care and specific changes to the training regime. Activity and training must be done without pain.
You may need to replace your regular runs with things like cycling or swimming. These take some of the load off bone, giving it time to recover.
You might also try a run on a deweighting treadmill.
Switching out runs for lower impact activities allows you to keep up your fitness as you recover.
If you ignore the stress fracture and keep training, you might get a full fracture of the bone. This means more time off of training and a longer recovery period.
Managing Risk Factors
The biggest risks come from poor nutrition and a training load that’s too high. Another thing that often gets overlooked is early sports specialization.
While this can be a problem for anyone, it tends to affect female athletes the most.
A combination of eating too little and burning too much means they don't get enough calories. And, as many have very low body fat, they don’t have much of a calorie reserve to buffer them.
Without enough calories, the body doesn’t have the building blocks it needs to remodel and repair. And it's worse if they're also not getting enough bone-building vitamins and minerals (like Vitamin D and calcium).
If the body doesn't get enough energy, it goes into starvation mode. It can shut down function in certain systems. This is why one of the hallmarks of low energy in women is lack of a period. Reproduction isn't as important as other more vital systems.
Female runners are, in fact, among the highest of those at risk for bone stress injury (BSI).
Thus, it’s crucial to focus on getting enough calories and nutrients to keep bones healthy. Coaches, families, and individuals need to be aware of this issue. Eating enough to fuel training is crucial.
If you’re struggling with food or there's been a big change in how you eat, it may be time to talk to a registered dietician. They can provide tailored help as well as point you in the direction of other resources. We’re quite partial to Julie Hansen – she an RD and exercise physiologist who specializes in this area.
Training load combines intensity - how hard your workouts are - and duration - how often/how long you work out.
If you add training load too fast, you’ll find yourself getting injured more often.
So many different things - like genetics, diet and nutrition, age, etc. - affect how you recover and progress.
Thus, what works for one doesn’t work for all. If you try to match training load to those around you, then it might be too much or too little for your specific needs.
Anyone in team sports, particularly track and field, needs to be aware of this.
And they may have to advocate for themselves. Sometimes the whole team does goes through the same exact workouts. This means that for some, the workouts will be great, and for others, they’ll lead to injury.
One of the best ways to manage this issue is by reducing the intensity in your training plan. For aerobic exercise, an 80/20 split of high-intensity to low-intensity is ideal.
This means most of your aerobic workouts should be low intensity. Even when adding more high intensity - like in peak training - the split should still favor low intensity.
This helps you build endurance and recover better. Yet you also keep the benefits of high intensity, like greater speed and longer time till fatigue.
One of the best ways to do this is with heart rate zone training. Heart rate is an excellent measure of intensity, so training in those zones will help you get the most out of every workout.
If you don’t know your zones, it’s a great time to get metabolic testing. Learn more here.
If you decide to add more intensity to your training, back off on how often/how long you train. This will allow your body to recover from the added stress. As you make progress, then you can add the time you're training back in.
To make recovery even better, pay attention to things like sleep and nutrition. These are crucial for good recovery.
Also pay attention to how you feel in the 24 hours after your workout. Do you feel a lot more tired and fatigued than usual? Are you having more pain than you usually experience? Do you feel like it’s taking you longer to recovery? Are you rapidly dropping body weight?
These can all be signs of adding training load too fast. And they may be indicators to back off and progress at a slower rate.
Early Sports Specialization
Bone building potential is at its highest in early years. So this is the best time to have kids be active in a variety of sports and activities.
Different movements, speeds, impacts, and intensities help athletes become stronger and more resilient.
In contrast, specializing too early can lead to burnout and injury. And for sports like running, cycling, or swimming it can be mean poorer long-term bone health.
The most positive adaptations in bone involve high impact over short periods of time.
Sports like cycling and swimming don’t provide high impact. And sports like running provide impact but do so over longer periods of time. This means neither are great for stimulating bone to adapt.
And runners have it even worse – they have among the highest rate of bone stress injury (BSI) among athletes.
As a rule, runners should include a rest day at least once a week and take 1 week off every 3 or so months.
Is There Anything Else I Can Do?
Managing diet and training load go a long way toward helping you avoid injury.
It's also important to add in plyometrics, strength training, and cross training. These will help further bulletproof you against injury.
Plyometrics can be a great addition to trigger improvements in bone strength. They involve the high impact, low frequency that provides an ideal stimulus to bone.
It doesn't take long for bone to get bored. So repetitive, high rep loading (like that seen in running) isn’t great for improving bone health.
Doing a variety of plyometric exercises adds a further benefit. It loads different areas of the bone with each exercise. This leads to the bone, as a whole, becoming more resilient.
Incorporating plyometrics as part of your regular routine also benefits your tendons. It improves their ability to store and release energy, which means less load on your bones.
Be sure to include strength training as a regular part of your fitness regime.
Training should use moderate to heavy loads. These are ideal for building muscle size and strength. This makes muscles better at absorbing shock and distributing forces across the bone.
Heavy loads also make tendons stronger, so they're better at storing and releasing energy. This takes stress off the bone and makes the activities you do less fatiguing.
Thus, people who strength train on a regular basis tend to have fewer BSIs.
Muscle strength is also important for long-term health. Stronger people tend to live longer.
Cross training is important because it can both strengthen bone and help it recover.
Activities like volleyball or basketball have high impact over short periods of time. Thus, like plyometrics, they provide a strong signal for bones to adapt.
Other activities, like cycling or swimming, help you stay conditioned. They work your heart and lungs while giving your bones a chance to rest and recover.
Cross training works your body in a variety of ways, so muscles, tendons, and bones get stronger.
While there’s always a ton of different reasons for bone stress injury, there’s a lot you can do to avoid it.
Pay attention to your nutrition and training load – it’s crucial for staying healthy.
Take part in a variety of sports, especially in younger years – this is an ideal time for building bone.
And make sure you're doing plyometrics, strength training, and cross training.