When someone develops an overuse injury, one of the first questions they usually ask is:
“What caused this?”
Was it the long run?
The new shoes?
The heavy workout?
The hill repeats?
The weekend of yard work?
Sometimes there is an obvious trigger. But with many overuse injuries, searching for one single cause can send us in the wrong direction.
A more useful question may be:
What set of interacting forces keeps producing this problem?
Or, put another way:
Sometimes the useful unit of analysis is the loop, not the event.
The Injury May Not Have Started With One Bad Movement
Consider a runner with Achilles pain.
Maybe they recently increased their mileage.
Their Achilles becomes sore, so they stop running for a week.
The pain settles down.
They assume the injury is healed and return to their previous mileage.
The Achilles becomes irritated again.
So they rest again.
Then they try running again.
And the cycle repeats.
It might look like this:
Training exceeds current capacity → pain → rest → capacity decreases → return to previous training → training exceeds capacity again → pain
At that point, the problem isn't simply the Achilles tendon.
The problem is the loop.
Research on running injuries increasingly describes them through a similar load-versus-capacity framework. Every tissue has some ability to tolerate repeated stress. Problems can develop when the cumulative load placed on that tissue exceeds what it is currently prepared to handle.
And importantly, that capacity is not fixed.
It changes.
Your Capacity Is Constantly Moving
Imagine your body has a certain amount of physical stress it can tolerate today.
That amount might be higher when you have been training consistently, sleeping well, eating enough, and gradually preparing your body for a particular activity.
But capacity can temporarily decrease.
Maybe you:
haven't exercised much for several weeks
suddenly increased your training
are coming back from another injury
haven't slept well
have been under significant life or work stress
added a new type of exercise
dramatically increased speed, hills, jumping, lifting, or another unfamiliar stress
The exact same five-mile run may therefore represent a very different challenge at different points in your life.
Five miles after months of consistent training may be routine.
Five miles after three weeks off may be a substantial workload.
The activity didn't necessarily become dangerous.
Your relationship to that activity changed.
That is systems thinking.
Instead of asking only:
“What activity hurts?”
we also ask:
“Why is this activity exceeding your capacity right now?”
The Boom-and-Bust Loop
One of the most common patterns we see in physical therapy is what I think of as the boom-and-bust cycle.
Someone feels good, so they do a lot.
Then they hurt.
So they do almost nothing.
They begin feeling better.
So they do a lot again.
Then they hurt again.
Over time, exercise becomes increasingly unpredictable.
Good day → big workout → flare-up → complete rest → feel better → big workout → flare-up
This can be incredibly frustrating because the person may conclude:
“Every time I exercise, I get injured.”
But exercise may not actually be the problem.
The dose may be the problem.
And the repeated cycle of overload followed by underloading may prevent the body from ever developing the capacity needed to tolerate the desired activity.
Rest Can Help—But Rest Doesn't Necessarily Build Capacity
Rest is sometimes appropriate.
If a tissue is highly irritated, temporarily reducing its workload can allow symptoms to settle.
But there is an important distinction between:
reducing load
and
eliminating load indefinitely.
Muscles, tendons, bones, and other tissues adapt to stress.
When appropriately dosed, loading is one of the signals that tells the body:
We need to become better at handling this.
Remove that stimulus for long enough and capacity can decrease.
This is why someone can feel completely fine after several weeks of rest and still experience pain when they return to their previous activity.
The symptoms disappeared.
But the system that produced the symptoms never really changed.
A Better Goal: Change the Loop
Good rehabilitation should therefore do more than simply make something stop hurting.
It should change the conditions that keep producing the problem.
That may mean temporarily reducing the irritating activity while maintaining other forms of exercise.
It may mean strengthening the tissue.
It may mean gradually rebuilding running mileage.
It may mean modifying how frequently someone performs a particular activity.
It may mean improving recovery.
It may mean changing technique when mechanics are placing unusually high stress on one area.
Usually it is some combination.
The goal is to move from:
load repeatedly exceeding capacity
to:
capacity gradually increasing until it comfortably exceeds the demands of your life or sport.
That is a very different way of thinking about rehabilitation.
Imagine Two Dials
One simple way to think about an overuse injury is to imagine two dials.
One dial is LOAD.
This includes things like:
running mileage
running speed
hills
lifting volume
lifting intensity
jumping
sports
work demands
repetitive movements
The second dial is CAPACITY.
This includes things like:
strength
tissue conditioning
training history
recovery
sleep
nutrition
previous injury
general fitness
If symptoms appear, we don't necessarily have to turn the load dial all the way to zero.
Instead, we can turn the load down slightly while gradually turning capacity up.
Over time, the gap between what your body can tolerate and what you ask it to tolerate becomes larger.
That gap is resilience.
This Changes the Question We Ask in Physical Therapy
When someone comes to Black Bear Physical Therapy with a recurring Achilles problem, knee pain, plantar fascia pain, shoulder irritation, or another overuse injury, of course we examine the painful area.
But we also want to understand the system surrounding it.
What changed recently?
What does your training week actually look like?
What happens when you feel good?
What happens when you hurt?
How much activity can you currently tolerate?
What activities do you need to get back to?
Are there strength or mobility limitations that may be changing how forces are distributed?
How quickly have you been progressing?
And perhaps most importantly:
What keeps recreating the problem?
Because sometimes the solution isn't finding the single thing that injured you.
It is finding the cycle that keeps bringing you back to the same place.
The Goal Isn't Just Less Pain
The ultimate goal of rehab shouldn't simply be:
“Make this stop hurting.”
It should be:
“Build a body that can comfortably handle the things I want to do.”
That usually requires more than treating a painful tissue.
It requires understanding the interaction between load, recovery, strength, training, and time.
Overuse injuries often aren't a single event with a single cause.
They are systems.
And once we can see the system, we have many more opportunities to change it.
Sometimes the useful unit of analysis is the loop, not the event.