If strength training was actually bad for runners, elite runners wouldn’t touch it.
But they do.
The reason most runners avoid lifting isn’t science—it’s stories.
Bad gym stories.
“Bulky” fears. “I don’t have time” excuses.
And a lot of outdated advice that keeps people stuck in the injury loop while they swear they’re “just not built for running.”
I’ve believed a few of these myths myself. And I’ve coached runners who were one good strength habit away from finally staying healthy.
So let’s shut the nonsense down.
Here are the biggest myths that keep runners away from strength training—and what’s true in the real world.
Myth #1: “I’ll bulk up and slow down.”
Nope. Not unless you’re eating like a powerlifter and lifting like a bodybuilder—and even then, it’s tough.
Lifting a couple times a week won’t make you balloon up.
In fact, most runners get leaner from lifting. Why? Because strength training helps you hang onto muscle while dropping fat. Your power-to-weight ratio improves, and that’s a good thing for speed.
And please don’t take my word for it.
The Journal of Strength & Conditioning Research and others have shown that mixing strength with running doesn’t lead to weight gain in endurance athletes.
In fact, all your running volume limits muscle growth—a thing called the interference effect. You stay light, just stronger.
Let’s be honest: Mo Farah lifts heavy. He doesn’t look like Schwarzenegger. He looks like a guy who can destroy a track meet. That’s what we’re after.
And ladies? You’ve got even less testosterone, so the idea of “accidentally getting bulky” is just a myth that needs to die already. What you will get is stronger glutes, better posture, and less risk of falling apart halfway through marathon training.
Myth #2: “Running already builds my leg strength.”
Wrong again.
Running builds endurance—it doesn’t build total-body strength.
It’s mostly your quads and calves working over and over.
That’s a pretty limited range of motion and muscle use.
But you’ve also got hips, glutes, hamstrings, core, and upper body that need love too—especially if you want to run well and stay injury-free. Most running injuries come from weaknesses that running can’t fix.
I’ve coached runners with “runner’s knee” for months, and when we finally focused on strengthening their glute medius, the pain disappeared. Not because they ran less—but because we filled a gap running couldn’t fill.
And remember: endurance training is catabolic—it breaks muscle down. Strength training helps flip that. It builds you up. It makes your tissues more resilient so they can take the pounding.
So no, running more is not the answer. Lifting is what lets you run more—without breaking down.
Myth #3: “I don’t have time for strength training.”
Honestly? You do. You’re just not prioritizing it.
You don’t need an hour a day or a fancy gym setup.
Two 20-minute sessions a week is enough to make a real difference.
That’s like shaving 2–3 miles off your weekly volume and reinvesting it in injury-proofing your body.
Would you rather skip a few miles now—or skip 6 weeks later when you’re laid up with tendonitis?
You can even tack strength onto your run days.
I like stacking a 20-minute session after my interval or tempo days. That way, my easy days stay truly easy. No need to overthink it.
Start small. Do 10 minutes of bodyweight work after two of your runs this week—push-ups, lunges, planks.
That’s it.
Build the habit. The hard part is getting started, not getting shredded.
So if you’ve been saying, “I don’t have time,” try this instead: “I haven’t made it a priority… yet.”
Myth #4: “I only need core work, nothing else.”
Let’s clear this one up fast. Yes, core strength matters. But thinking you can plank your way to injury-proof running? That’s a rookie mistake I’ve seen too many runners make—including myself in my early days.
Here’s the truth: most running issues don’t come from weak abs.
They come from what’s below and around them—your hips, glutes, and lower legs.
You can have a six-pack and still run like a wet noodle.
Take the gluteus medius—the little side hip muscle most runners ignore.
If that’s weak, your hips drop when you run, your knees wobble, and before long, you’ve got IT band pain screaming down your leg.
I’ve coached runners with textbook abs who still ended up limping because they skipped their hip work.
Studies have linked weak glutes with IT Band Syndrome—and trust me, no amount of crunches will fix that.
Same goes for shin splints.
Most of the time, they come from weak tibialis anterior muscles and under-trained calves.
Plantar fasciitis? Often caused by weak feet and lazy arches.
Again, your core didn’t cause that. Your forgotten leg muscles did.
And even when we say “core,” we’re not just talking about your abs.
It’s your lower back, obliques, hip flexors, glutes—the whole trunk.
So if your idea of core work is three sets of sit-ups and a selfie, you’re missing the point.
A runner who only trains their abs might still collapse at the hips, roll their ankles, or lose posture halfway through a 10K.
Why? Because your body works as one big unit.
If one part slacks off, something else has to pick up the slack—and that’s how imbalances (and overuse injuries) sneak in.
I’ve seen this story play out hundreds of times. A runner has strong abs but weak glutes… and they wonder why their lower back hurts after every long run.
Here’s what actually works:
- Hip work – Think clamshells, banded walks, and single-leg glute bridges. These fire up the stabilizers.
- Leg strength – Squats, lunges, step-ups, deadlifts. These build real-world strength where you need it.
- Upper body? Don’t skip it. A strong upper back and shoulders help with arm swing and upright posture, especially late in races when form falls apart.
And good news: compound moves like deadlifts hit everything—your core, glutes, back, even grip. So you don’t need to ditch core work, just don’t stop there.
My coaching tip: Start small. Pick one lower-body lift, one glute move, and a couple of upper body basics. Keep it simple, but keep it consistent.
Myth #5: “Strength training will make me inflexible.”
I used to believe this one too. That lifting weights would turn me into a stiff-legged robot who couldn’t touch his toes.
I imagined I’d go from runner to bodybuilder overnight. But here’s what I learned—and what research now confirms—it’s simply not true.
In fact, strength training done the right way can increase your flexibility.
A study in the International Journal of Exercise Science followed people doing resistance training for six months—and guess what? Their shoulder and hip flexibility actually improved.
Another study even found that lifting through full range of motion (think deep squats, full lunges) was just as effective for boosting hamstring flexibility as traditional stretching.
Why? Because when you train at end ranges—meaning your muscles are stretched and under tension—they adapt. They get stronger in that stretched position.
They don’t lock up. They learn to move better, not worse.
If anything, I’ve found that strength training helps highlight your weak spots.
One side tighter than the other? You’ll feel it. You’ll fix it. And once those imbalances start to go away, you’ll move more smoothly, more powerfully, and yep—more flexibly.
Here’s the catch: form matters.
Half-reps won’t help.
Ego-lifting won’t help.
You’ve got to go deep (within your own safe range) and control the movement.
Want more mobility? Try this:
- Add deep squats to your week.
- Do overhead presses with full shoulder movement.
- Warm up with dynamic stretches.
- Toss in some mobility drills—hip openers, ankle rolls, foam rolling.
And just to be clear: it’s not lifting that makes runners tight. It’s usually running itself. All those miles in the same direction? That’s what shortens your hip flexors and stiffens your calves. Lifting can actually undo that damage—if you train the opposite muscles.
So if you’re avoiding strength work because you’re afraid of becoming stiff, you’ve got it backwards. Lifting smart will help you stay mobile. You just have to do it right.
Quick gut-check: When’s the last time you stretched after a run? Or lifted something that forced your joints to move fully? Be honest.
The truth: Done right, lifting helps you move better, not worse. It won’t make you the Tin Man. It’ll make you tougher, smoother, and more resilient.
Myth #6: “Strength training is too complicated”
Let me be blunt: this one’s just fear talking. And I get it—I’ve stood in gyms not knowing what the hell to do with a dumbbell. But strength training doesn’t have to be complicated.
You don’t need fancy programs, apps, or certifications. You just need a handful of movements and the willingness to show up.
Start with bodyweight: squats, lunges, push-ups, planks.
Add in basic dumbbell lifts: goblet squats, rows, shoulder presses.
Learn the moves. Focus on clean form. Ask a trainer if you’re unsure—one quick session can save you months of mistakes.
It’s like learning to run. You didn’t know how to pace yourself at first. But you figured it out. This is the same. You learn, you lift, you get stronger.
And trust me—once you get past that awkward first week, strength training will become something you look forward to. Because you’ll feel it. In your running. In your posture. In your confidence.