When Calf Raise Data Sounds Impressive—but Means Very Little
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If I tell you calf raises produce more intrinsic foot muscle activation than isolated foot exercises, that sounds impressive.
If I tell you patients should hit a certain number of heel raises to “pass” plantarflexor testing, that sounds objective.
But neither statement necessarily tells us anything useful about whether a patient is actually getting better.
And that’s the problem.
The Calf Raise Testing Illusion
Single-leg heel raises are everywhere in physical therapy.
They’re taught as:
a strength test,
a return-to-function benchmark,
a way to assess plantarflexor capacity.
But what are we actually measuring?
A standing calf raise is not an isolated strength test. It’s a mix of:
balance,
motor control,
load tolerance,
foot stiffness,
tendon behavior,
and yes… plantarflexor contribution.
If a patient performs poorly, what does that actually tell us?
Is it:
weakness?
pain inhibition?
poor strategy?
forefoot discomfort?
balance limitation?
We don’t know.
And yet, we often treat rep counts like they’re precise indicators of strength.
They’re not.
They’re just easy to measure.
The EMG Seduction Problem
A recent paper examined intrinsic and extrinsic foot muscle activation across common exercises.¹
It found that:
certain calf raise variations produced high intrinsic foot muscle activation,
adding load or forward lean increased activation and torque output.
Interesting? Yes.
Clinically decisive? Not even close.
Because EMG tells us one thing:
electrical activity increased during a task.
It does not tell us:
that meaningful strengthening occurred,
that symptoms improved,
that function improved,
or that outcomes changed in any meaningful way.
And yet, the takeaway circulating online was:
“Strengthen the calf and foot intrinsics with one exercise? Yes please!”
That conclusion wasn’t proven.
It was assumed.
Ash Nazg Dur Calf Raises?
(One Exercise to Rule Them All? Not So Fast.)
We love shortcuts in rehab.
The idea that one exercise can “hit everything” is incredibly appealing:
efficient,
simple,
marketable.
But it’s also rarely true.
Yes—calf raises likely create more intrinsic foot muscle activation than isolated “short foot” exercises.
That shouldn’t surprise anyone.
You’re:
loading the entire system,
moving through larger ranges,
interacting with the ground,
managing bodyweight.
Of course activation is higher.
But here’s the key question:
Why does that matter?
Does it:
reduce plantar heel pain?
improve running performance?
decrease injury risk?
help someone return to sport?
improve daily function?
We don’t know.
Because the study didn’t measure any of that.
Interesting Finding, Wrong Conclusion
This is where rehab reasoning often breaks down.
We take a real, valid finding:
“Exercise A produces more muscle activation than Exercise B”
And we extend it into something it was never designed to answer:
“Exercise A is better for patients”
That leap is not evidence-based.
It’s assumption layered on top of measurement.
Surrogate Metrics Are Not Outcomes
This is the common thread between both issues:
What we measure. What we assume
Heel raise reps. strength/function
EMG activation. effectiveness
Both feel objective.
Both sound scientific.
But neither guarantees meaningful change for the patient.
What Actually Matters
Patients don’t come in asking:
“Can you increase my intrinsic foot muscle EMG?”
“Can I get to 25 heel raises?”
They want to:
run,
jump,
walk without pain,
return to sport,
maintain independence.
So the better questions are:
What is their goal?
What is limiting them?
What can they tolerate today?
How do we progressively bridge that gap?
If a test or exercise doesn’t help answer those questions…
its value should be questioned.
Final Thought
We didn’t prove that calf raises improve outcomes—we proved they produce a signal. And then we treated that signal like a solution.
The goal of rehab is not to activate muscles more.
It’s to help people move better, feel better, and return to what matters to them.
If a finding doesn’t help us do that, then it’s not wrong—
it’s just incomplete.
References
Osborne, JWA, Menz, HB, Landorf, KB., et al.. The influence of body posture and added mass on intrinsic and extrinsic foot muscle activation and force output during common foot strengthening exercises. Journal of Sport and Health Science. 2025. Available at: https://www.sciencedirect.com/science/article/pii/S2095254625001188
RightHab Insight:
Not everything that can be measured needs to guide care.