Why Runners Get Hurt

You’re a runner. You love running! And some days, you have perfect running days. But then there are those other days – the days you feel less than great. The days that the P word comes to get you: Pain. 

Maybe it’s a small pain. Maybe a friend tells you something like, “Rub it out with a lacrosse ball for 45 minutes a day,” or “That happened to me, and foam rolling fixed it.” And it sounds hopeful! So you go to work rolling or rubbing on this annoying pain spot for hours of your day… but the pain persists. 

And because you’re a runner and running is your hobby or your sport or your happy place, you’re asking the million-dollar question: Am I injured? Why am I in pain? And what can I do to fix it? 

Pain vs. injury

We differentiate between pain and injury because they are not synonymous! They are related and can exist on the same continuum. But hear me when I tell you – not all pains are injuries (or even turn into injuries!) And, believe it or not, not all injuries cause pain.  

Pain is your body’s warning system; it’s telling you “Hey, pay attention to this!” But that doesn’t necessarily mean something is wrong, just that something wants attention. 

For us, injury is the body at risk. Injury means something is wrong, and frequently means a cessation of activity (or specific activities) due to the risk of more serious problems.  

With most runners, pain usually signals a need to modify training and running, but not a need to stop running altogether. Before stopping running, we look for activities and movements that are tolerated by your pain and won’t continue to set you back.

The effects of running on the body

We can’t talk about running pain without talking about stress and adaptation. Our bodies were built to adapt to stress and running is a stressor. Let’s talk about how running impacts your body (keeping in mind that adaptation rates vary from person to person!) 

Bones 

Every step you take puts stress on your bones, causing tiny disruptions to their surface. Your body comes to the rescue with its trusty bone crew: osteoclasts and osteoblasts. Osteoclasts (specialized bone cells) remove damaged tissue, and osteoblasts (other specialized bone cells) deposit new bone in its place. With consistent stress and a balanced rate of rebuilding, your bones become thicker, stronger, and more resistant to future stress.

But there's a catch! This bone-building process works best when you're consuming enough calories. If you’re running on a caloric deficit, you increase your risk of stress fractures – so make sure you’re fueling your body! 

Muscles

That post-run soreness you feel? It's not lactic acid, as you might have heard. Lactic acid is cleared from muscles very quickly and does not cause lasting sensation.

What you’re actually feeling is the tiny muscle tears caused by the stress of running. As you adapt to this stress, the activities that used to cause soreness will cause less and less soreness over time – because your muscles are repairing themselves and become stronger and more resilient with every repair. Congrats, you've adapted!

Tendons

Tendons, all your tough connective tissues, adapt in a different way but basically follows the same principles: stress the tissue, break it down, build new tissue in it’s place. 

The difference is that tendons don’t have their own blood supply, so getting nutrients to those tissues takes longer. As a result, your tendons heal and adapt more slowly than your muscles do. This is where a lot of runners get in trouble! Your muscles feel good, but your tendons haven’t caught up yet. Pushing your tendons beyond their adaptation capacity can result in tendonitis or tendinopathy.

So, what causes pain and injury in runners? 

Too much mileage too soon

Simply tracking miles doesn’t consider the total stress load placed on the body. Whether you’re a new runner, a seasoned elite, or anyone in between, that is what you are doing as you increase your mileage – increasing the stress on your body. 

Now that we know what the effects of running are on the body, we know that increasing stress on the body without getting the proper amount of recovery can lead to pain! Too much mileage too soon = too much stress too soon. Build your miles slowly to make sure you give your body adequate time to repair. 

Too much intensity too soon

When building mileage, you also have to consider that not all miles are equal. An easy 3-miler is not the same as a 3-mile tempo run. Why? Long runs, tempos, fartleks, hills, and intervals place an exponentially higher level of stress on the body. The harder you run, the harder the impact on your legs, and the more force that they absorb (think: the pounding, jolting feeling in your legs as you run downhill!) 

Yes, we’re talking about stress again! All these runs that aren’t easy miles = more stress on your body tissues = needing to take more time to recover. We recommend dropping some easy miles (or whole easy runs!) in your weekly plan if you’re adding intensity to other runs in your week – especially early in a training plan when you’re just starting to introduce intensity!

How do you build mileage as a runner? How can you figure out how much intensity to add to your weeks? There’s no hard and fast rule, but this is our take on it. 

Not enough of other things

Runner’s run. It’s what we do. However, what that means is that we typically don’t do anything that isn’t running. 

Cross-training is a four-letter word in the running community, but guess what – it’s helpful and it’s good for you! People know that crosstraining can be a valuable way to build things like cardiovascular endurance, but for runners, crosstraining can be particularly valuable in keeping your muscle tissues engaged while giving your connective tissues (read: tendons!) time to catch up in their repairing process. 

What are we talking about when we talk about cross-training? Yes, we’re talking about things that keep your body moving, like swimming and cycling. But we’re especially talking about things that keep your muscles engaged and strengthening without putting a lot of stress/impact on your connective tissues; specifically, strength training. 

We know, we know, “strength training” is every runner’s least favorite phrase. But the science is clear! Runners who routinely strength train are significantly less likely to get injured, more so than any other type of cross-training.  Find out more about why strength training is so valuable, particularly for runners. 

TL;DR

If you’re reading this article, I’m guessing that you’re in pain or injured, and you're asking yourself what happened. The long and short of it is, It’s not your shoes, it’s not your biomechanics – it’s your training. Overtraining, too much mileage, too much intensity, all of it too soon, is the number one reason you’re in pain. 

You need to give yourself and your body the time it needs to heal and adapt, or else your likelihood of pain and injury increases exponentially.