Can Muscle Imbalance Lead to Injury?
Did A Muscle Imbalance Lead to My Injury? The Story of My Foot Break
A few weeks before I broke my foot in July of 2024, I stood in my garage with a tape measure and recorded a video of myself measuring my calves. Still kills me how insane this timing was between the two moments. Take a read.
I wasn't doing it because I suspected something was about to snap. I was doing it because I'd finally noticed something I had somehow overlooked for years: my right calf was visibly, dramatically bigger than my left. Not "one side is a little more defined" bigger. We're talking close to a full inch of difference at the thickest point.
Then, a few weeks later, I broke my right foot. The bigger side. The stronger side. The side that had been quietly doing extra work for over a decade.
So today I want to answer a question I've been chewing on ever since: can this type of muscle imbalance lead to such a big injury? I'll share my story, the actual measurements from that garage video, what the research says, and what you can do about your own imbalances before your body forces the issue like mine did.
The Short Answer: Yes, Muscle Imbalances Can Contribute to Injury
Obviously there’s a general assumed truth here and there’s no way to know everything that’s happened before an injury or what will happen, etc. However, I think it’s worth digging into more, because there’s not a lot that gets done or improved in most cases after the statement or question asked above gets laid out on the table. I think in most scenarios we just say that this can happen, and then we go about our business. We don’t change the program and then pain and issues show up, but might be long enough between or even seem completely unrelated to the last one. Therefore, we “got through it.” mentality comes into play. Even subconsciously.
Based on both my experience as a strength coach and what the research shows, muscle imbalances absolutely can contribute to injury, especially in runners.
But here's the nuance most fitness content skips: an imbalance is rarely the only reason someone gets hurt. Training load, recovery, sleep, old injuries, footwear, terrain, and life stress all stack on top of each other. An imbalance is one card in the deck. Sometimes it's the card that tips the whole hand.
Nearly every runner has some degree of asymmetry. Nobody is perfectly symmetrical, and chasing perfect symmetry is a waste of your time. The question isn't "do I have an imbalance?" The question is: is my imbalance big enough, and has it been around long enough, to change how my body absorbs force?
Mine was. And I have the video to prove it.
The Video I Wish I'd Paid Closer Attention To
I recently found the video on my phone, and honestly, it's fascinating and a little haunting to watch now. Well not haunting, but you get the picture. It’s annoying
I was training in my gym at the time, I was also in some of the best running shape of my recent life, and I noticed the definition difference between my right and left calf. Actually a client and I noticed it. It was kind of a funny moment to be honest.
My left side had been my "problem side" for years. A lot of posterior tibialis pain. Medial calf pain. What I thought was plantar fasciitis at one point. Achilles tendonitis at another. There was always something nagging on the left.
Because I don't spend much time looking at myself, I had never actually put a tape measure on my legs to quantify what was going on. So I finally did, later in my garage, on camera. Hopefully just to document my progress, and boy did it!
The Numbers From My Garage
I measured several spots on both lower legs. Here's roughly what I found:
Measurement Spot: Upper lower leg
Right Leg: 9 in
Left Leg: 8 13/16 in
Difference: ~3/16 in
Measurement Spot: Base of the calf
Right Leg: 12 in
Left Leg: 11 1/2 in
Difference: ~1/2 in
Measurement Spot: Thickest part of the calf
Right Leg: 15 3/4 in
Left Leg: ~15 in
Difference: Almost a full inch
These were garage tape-measure numbers, not lab-grade data. But you don't need a lab to see that a difference approaching an inch at the meat of the calf is significant. That's not a rounding error. That's years of one leg doing more work than the other.
And here's the part that still gets me: the bigger, "stronger" side is the one that broke.
How Did I Get Here? A Decade of Compensation
When I traced the story backward, the imbalance made perfect sense.
My right side is my dominant side. For many years before the foot break, I dealt with recurring issues in my right low back and right hip. My left leg was the one that always hurt, so my right leg quietly picked up the slack. Every push-off, every stride, every workout, my right side was pushing a little harder.
Do that a few thousand times per run, a few hundred thousand times per year, for over a decade, and you build a leg that's an inch bigger than its partner. You also build a leg that's absorbing more repetitive stress than it was ever meant to handle.
This is the sneaky thing about compensation patterns:
The painful side gets your attention. I spent years treating my left calf, left Achilles, and left foot.
The compensating side gets the workload. My right leg was silently overloaded the entire time. Which really wasn’t a surprise, but the end result sure was.
The overloaded side often breaks (not necessarily bone) first. Bone, tendon, and muscle all have a stress budget. Blow past it long enough and something gives.
I've now coached long enough, over 15 years as a personal trainer and strength coach, to know my story isn't unusual. It's just unusually well documented, because I happened to film my calves a few weeks before the break.
What the Research Says About Muscle Imbalance and Injury
I don't want this to be just "trust me, bro" content, so let's look at what we actually know.
Muscle imbalances have been studied for decades in sports medicine. Research has linked strength imbalances, like the hamstring-to-quadriceps ratio, with increased risk of hamstring strains and knee injuries. Studies on hip strength have found associations between weak hip stabilizers or rotators and lower leg injuries in athletes. And virtually every clinician who works with runners will tell you that side-to-side asymmetries show up constantly in injured athletes.
That said, I want to be honest with you, because honesty matters more to me than a tidy narrative: the research is mixed. Some imbalances correlate clearly with certain injuries. Others don't show a strong connection. Scientists can't always predict who gets hurt based on asymmetry alone, because injury is multifactorial. Training errors, like ramping up mileage too fast, are still the biggest driver of running injuries.
So here's the grounded takeaway: a muscle imbalance is a legitimate risk factor, not a guaranteed sentence. Think of it like driving with one worn tire. You might drive fine for years. But you're carrying extra risk every mile, and if conditions get rough, that's the tire that fails.
In my case, conditions got rough. I was training hard, pushing my fitness at least slightly, and the leg carrying the extra load ran out of budget. I mean, it truly was an accident. Not like an ankle roll off the curb type of accident, but
Why Runners Develop Muscle Imbalances
If nearly all runners develop some asymmetry, it's worth understanding where it comes from. In my experience coaching runners of every level, including my work as a strength coach for a collegiate cross-country team, these are the biggest culprits:
1. Old Injuries That Never Fully Resolved
This was my story. Pain changes movement. Even after the pain fades, the movement pattern often sticks around. Your body is brilliant at finding workarounds, and terrible at un-finding them without deliberate work.
2. A Dominant Side
Everyone has one. Your dominant leg pushes off harder, balances better, and volunteers for extra duty in every lunge, stair climb, and stride. Left unchecked over years, that adds up.
3. Doing Only One Thing, Forever
I stand against training the same way forever. Only running, only one lift, only one movement pattern. The body thrives on variety, challenge, and change. When you feed it the exact same repetitive stress every day, imbalances don't get exposed or corrected; they get reinforced. Not variety as in “no plan,” just to be clear.
4. Road Camber and Terrain
Roads slope toward the gutter for drainage. If you always run the same side of the same road, one leg is effectively running slightly downhill for every mile. Trail runners deal with their own version through uneven terrain.
5. Skipping Strength Work Entirely
Running builds fitness, but it doesn't build balanced strength. Without some form of strength training, especially single-leg work, small asymmetries have nothing pushing back against them.
Warning Signs of a Muscle Imbalance
You don't need to wait for a break like I did. Here are the signals I tell my athletes to watch for:
One side always hurts. If your "problem side" is a permanent character in your training story, ask what the other side is doing to compensate. Dig a little. Try out some theories and keep track, which I understand is not easy to do.
Visible size differences. If you can see a clear difference between your calves, quads, or glutes, believe your eyes. Mine were telling me the truth for years before I looked deeper. I did a lot of little things like the stretches, seeing specialists like chiros and PT’s and a lot of strength work. However, now knowing this, I want to try re-engaging in size differences a little more often in my training.
One side is always sore after runs. Uneven soreness usually means uneven workload. Usually.
Uneven shoe wear. Check the soles of your running shoes. Dramatically different wear patterns are a free gait analysis.
Single-leg tasks feel wildly different. If a single-leg calf raise or single-leg squat feels solid on one side and shaky on the other, that gap matters.
How to Check Yourself at Home
You don't need fancy equipment. You need a tape measure, a wall, and about ten minutes. Here's a simple self-check I recommend:
Measure your calves and thighs. Measure the same spots on both legs (thickest point of the calf, and a consistent point on the thigh). Write the numbers down with the date. A quarter inch of difference is normal life. Big differences, like my near-inch gap, deserve attention.
Single-leg calf raise test. Hold a wall lightly for balance and do slow, controlled single-leg calf raises on each side. Count how many quality reps you get before form breaks down. Compare sides.
Single-leg balance. Stand on one leg for 30 seconds per side. Notice which side wobbles, grips the floor with your toes, or fatigues first.
Single-leg sit-to-stand. From a chair, stand up on one leg with control, then lower back down. Compare effort and stability side to side. You can do this slightly or mostly assisted too, for now. Just don’t cheat.
None of this is a diagnosis. These are clues. But clues that shouldn’t be ignored, so don't repeat my mistake. If something hurts or a difference is dramatic, get evaluated by a physical therapist or sports medicine professional who can watch you move. Trust me, I thought I had been doing the right stuff for years. These little signs can sometimes just be a mistake, and I don’t shame myself for it, but either way, I should have gotten evaluated for calf size differences and a few others.
What I Did to Rebuild After the Break
Breaking my foot delayed the correction plan I had literally just started. That's the frustrating irony of the whole story: I finally identified the problem, began addressing it, and then had to sit out and heal first.
But once I could train again, here's the approach I took, and it's the same philosophy I use with every runner I coach: movement first. Before we chase paces, mileage, or aesthetics, we make sure the body knows how to move well. When you move well, everything else, strength, confidence, resilience, starts to fall into place.
My rebuild focused on:
Single-leg strength work. Single-leg calf raises, step-ups, split squats, and single-leg deadlifts. Bilateral lifts let the strong side cheat; single-leg work makes each side pay its own bill.
Extra volume for the smaller side. I didn't train my left leg the same as my right. I trained it more, deliberately, to close the gap. I’m pretty close now to both sizes the same. Definitely over half way through the process.
Foot and lower-leg specific work. Posterior tibialis strengthening, controlled calf work through full range of motion, and foot intrinsic exercises. The little muscles matter.
A well-rounded weekly structure. Weightlifting, cardio, and mobility together. Not just running. Not just lifting. The combination is what builds a body that lasts.
Patience and consistency over intensity. Not perfect, but persistent. Showing up on the boring days is where the real change happens.
The Update: My Left Calf Is Now the Bigger One
Here's the part of the story that gives me hope, and should give you hope too.
After months of deliberate rebuilding, my left calf, the historically smaller, historically painful one, is much closer to the right. My best estimate is the two sides are within about a third of an inch of each other, which is a massive improvement from a near-inch gap.
More important than the tape measure: the left-side pain is mostly gone. The posterior tib pain, the nagging calf issues, the neuromuscular weirdness I'd lived with for years, dramatically reduced. My legs are sharing the workload the way they were always supposed to.
I'll be filming an updated measurement video to document the numbers, because I believe in showing the work, not just talking about it. But the lesson is already clear to me: imbalances can be trained. Resilience can be built. The body responds when you give it a real plan and keep showing up.
What This Injury Taught Me
I became a trainer in the first place because my body fell apart when I was 24, right when I was in the best shape of my life. That experience taught me more than any textbook ever could. This foot break was a smaller version of the same lesson, and it reinforced a few beliefs I hold deeply:
Pain is a messenger, but it doesn't always report from the crime scene. My left side hurt for years. My right side broke. Treat the pattern, not just the pain.
Most people overthink fitness and underthink movement. You don't need a biohacking stack. You need to know how your body moves, and where it's cutting corners.
Setbacks are part of the work. There will be hard days and delays. The plan isn't to avoid every setback; it's to keep showing up through them.
Strength training and running together give you a foundation nothing else can. If I only ran, I'd probably still be stuck in that compensation loop.
Don't Wait for the Break
If I could go back and talk to the guy in that garage video, I'd tell him two things. First: good job finally measuring, that took years too long. Second: this is urgent, not interesting. An inch of difference isn't trivia; it's a warning light.
So here's my challenge to you. This week, grab a tape measure. Do the single-leg tests. Look at your shoe wear. Pay attention to the side that's always sore, and ask what the other side has been carrying for it.
And if you find something, do something about it. You don't have to figure it out alone. Whether it's through my running programs or personal coaching, my whole mission is helping runners get stronger, faster, and more injury resilient, so your body can handle whatever life throws at it.
Ready to build a more resilient body? Explore my running programs or book a free 15-minute call and let's find your imbalances before they find you.