One of the most common conversations I have with athletes, especially those coming back from an injury, goes something like this:
“I’m not sure if what I’m feeling is normal or if I should be worried.”
It’s a great question. And honestly, it’s one of the most important things an athlete can learn to answer for themselves. Because the line between “your body is adapting” and “your body is sending a warning signal” isn’t always obvious, especially when you’re in the middle of a return to run program, and everything feels a little uncomfortable.
So let me share the framework I use with my patients every day.
The Concept of Earned Soreness in Runners
The first thing I tell athletes when they start a return to run program — or when they ramp up their training in any way — is this:
Some soreness is earned. And earned soreness is okay.
Earned soreness is the muscle fatigue and achiness that comes from reintroducing your body to an activity, or from progressing that activity. You started running again after six weeks off. You lifted heavier than last week. You added sprint intervals to your program for the first time.
Your muscles weren’t ready for that load. They are recovering and adapting to that load. That’s not a problem, that’s the process.
Earned soreness typically:
- Shows up 12–48 hours after the activity (this is what exercise scientists call DOMS or delayed onset muscle soreness)
- Feels like a diffuse, achy heaviness in the muscle belly itself
- Is spread across both sides or across a general area
- Improves with gentle movement and light activity
- Fades within 2-3 days
When an athlete comes back from a stress fracture or a knee injury and tells me “my legs feel heavy and sore after my run,” I’m not worried. That’s earned. Their cardiovascular system might be ready to run, but their musculoskeletal system is catching up. We expect that and plan for it with our return-to-run program, which includes soreness guidelines.
Also, if you’ve just ramped up your long run or added hill intervals, you probably earned that soreness. Keep monitoring your training load to make sure you’re not ramping up mileage and/or intensity too quickly. Training load errors are the most common cause of injury in runners.
If you’re sore in a way that has nothing to do with what you did yesterday, that’s a different conversation.
What Unearned Pain Looks Like in Runners
Unearned pain is what I want athletes to pay attention to.
This is pain that doesn’t make sense given what you’ve done. Pain that shows up without a clear cause. Pain that stops you from moving the way you normally would. Here’s how I describe it to my patients:
It’s in the same area as your injury. If you’re coming back from a hip flexor strain and you feel a sharp pull in the front of your hip during your run (not muscle fatigue, but that specific feeling), that’s not earned. That’s your body telling you something isn’t right yet.
It’s one-sided in a way that concerns you. General bilateral muscle soreness after a hard workout? Earned. A specific ache that’s only on your left side, in the same spot, every time? Worth paying attention to.
It gets worse during activity, not better. Earned soreness often loosens up as you warm up and move. Pain that intensifies as your run goes on, or that forces you to alter your stride or stop altogether, is a signal worth paying attention to.
It doesn’t improve with rest. If you’re still feeling the same pain 5-7 days later with no improvement, that’s not normal adaptation. That’s your body asking for attention.
A Special Note on Tendons
One thing I’m always careful to explain to athletes is that it is okay for tendons to be sore.
Tendons respond differently to load than muscles do. They like progressive loading. In fact, controlled tendon loading is part of how we rehab tendinopathies. So if you’re returning from an Achilles issue or a patellar tendinopathy and you feel some soreness in that tendon after a run, that’s not automatically a red flag.
What we’re watching for with tendons is the response after the fact. A little soreness during or after activity that settles down within 24 hours and doesn’t get progressively worse week to week? That’s within acceptable limits during a return to activity. Tendon pain that’s getting louder, more frequent, or more limiting over time is telling you the load is too much, too fast.
The key question with tendons: is it settling down between sessions? If you’re recovering between runs and the baseline isn’t creeping up, we’re generally in a good place. If every run leaves you a little worse than the last one, we need to adjust.
Bone Stress Injuries Are a Different Story
I want to be clear about one category where I have a much lower tolerance for pushing through: bone stress injuries.
If you’ve had a stress reaction or stress fracture, or if I have any suspicion that what you’re feeling might involve bone, we are significantly more conservative. Bone stress injuries do not respond well to “push through it.” The consequences of continuing to load a bone that’s under stress can be serious. A stress reaction becomes a stress fracture, and a stress fracture becomes a complete fracture. These injuries can derail a running career if not handled appropriately.
With bone stress injuries, the signals I take seriously include:
- Point tenderness directly on the bone (not the muscle around it)
- Pain that gets worse as a run progresses and doesn’t improve with warm-up
- Night pain or pain at rest
- Pain with activities that shouldn’t be loading that area
If any of those are present, we stop, and we investigate. No exceptions.
Return to Run: What Normal Should Feel Like
For athletes in a return-to-run program, here’s the honest truth: it’s not going to feel perfect, and that’s okay.
Your body has been through something. It’s rebuilding. There will be days that feel harder than they should, muscles that are tired in ways they weren’t before your injury, and a general sense that things feel “off” compared to where you were.
That’s normal. That’s adaptation.
What we’re trying to avoid is the athlete who confuses all discomfort with danger and stops before they need to, and equally, the athlete who confuses dangerous pain with normal discomfort and keeps going when they shouldn’t.
The framework I give every athlete I work with:
Ask yourself these three questions:
- Did I earn this soreness based on what I did?
- Is it in the same location as my injury, or is it one-sided and specific?
- Is it improving between sessions, or getting worse?
If you earned it, it’s general, and it’s improving, keep going. If it’s unearned, specific, or not improving, let’s talk before your next session.
When In Doubt, Ask
Here’s the other thing I always tell my patients: you are never bothering me by asking.
I would rather get a text or a call between sessions than have an athlete push through something they shouldn’t and set their recovery back by weeks. Part of what we do at Omega Project PT is be available to help you make those judgment calls. Sometimes it isn’t obvious, and having a second set of eyes (or ears) makes all the difference.
If you’re a runner, a triathlete, or an active person in the Wilmington area who’s trying to figure out whether what you’re feeling is earned soreness or something that needs attention, come in and let us take a look. That’s what we’re here for.
Book your assessment at Omega Project PT
Omega Project PT is located in Wilmington, Delaware, serving athletes across the greater Wilmington area, including Newark, Hockessin, and surrounding communities.
