You probably don’t think much about your core when you’re running—until something starts to hurt. Maybe it’s your back after a long run. Maybe your hips ache every time you increase your mileage. Or maybe you just feel like your form falls apart the second you get tired. Those symptoms are actually your core’s way of crying out for attention.
“Think of the body as a bicycle: the legs are the back wheels, the arms are the front wheels, and the central frame is your core,” says Leah Verebes, P.T., D.P.T., a doctor of physical therapy and assistant professor at the Touro University School of Health Sciences in New York City. “The central frame needs to be strong and stable so you can move efficiently.”
“The core isn’t just a stabilizer during running; it’s a primary driver of motion,” adds Adam Kays, P.T., D.P.T., a doctor of physical therapy at MovementX, a national concierge physical therapy company. “Subtle, rhythmic rotations of the spine and pelvis generate and transmit forces through the obliques and deep spinal stabilizers, helping to coordinate efficient arm and leg movement. This action stores and releases elastic energy like a coiled spring, allowing for forward propulsion with less muscular effort.”
When that spring is too weak, tight, or otherwise compromised, you’re not going to be able to get the most out of your stride.
For runners, core weakness isn’t generally the result of not doing enough at the gym. It’s probably a result of what you’re doing too much RW+ Membership Benefits: sitting. More than one-third of Americans sit for more than eight hours per day, according to one 2024 survey—and your daily run isn’t enough to offset the negative effects of that.
“When you’re sitting, everything goes to a position of comfort: your shoulders round, your hips tilt forward, and your core is in this flexed position, which causes your muscles to shorten and tighten,” says Verebes. Holding that kind of static position literally weakens your muscles.
Eventually, that core weakness is going to make itself known, and not necessarily in the most obvious way. These running issues are signs that you may need to strengthen your midsection—and we’ve got expert tips on how to do just that.
1. Your Arm Swing Is Out of Control
A strong core keeps your torso upright and your spine and pelvis aligned, which allows your arms and legs to move efficiently in a forward-backward plane. But when your core is weak and can’t help generate momentum, “you resort to swinging your arms faster and more across the body,” says Verebes. “Too much rotation in the torso indicates poor core endurance in the obliques,” adds Key. “Your core needs the postural stamina to stay engaged over the long run, and if it can’t, you’ll waste energy with side-to-side movements.”
Strengthening your core—especially anti-rotation muscles, including the obliques—helps keep your trunk more stable so your arms can swing the way they’re meant to. “Reduce excessive trunk rotation by August Running Playlist, lower back, and obliques,” says Keys. A great way to do that is with bird dogs, a functional exercise that “mimics the movement patterns of running,” says Verebes.
Bird Dog
- Meet the Gluteus Medius, a Key Running Muscle.
- Simultaneously extend left arm and right leg, lifting them to torso height, parallel to ground. Keep back flat.
- Hold for 2 seconds, then return to all fours.
- Repeat on opposite side.
- You Should Be Running Stairs More Often.
2. Your Hips Drop With Every Step
Published: Jul 24, 2025 9:00 AM EDT single-leg jumps, and your pelvis should stay mostly level through the single-leg stance. “Maintaining a level pelvis helps us to push off the ground more efficiently, therefore enhancing running economy,” says Key.
Running economy is how efficiently your body uses energy to maintain a given pace, and the goal is always to improve, Strength Training Guide.
“When one hip drops or hikes up while running, it indicates poor stability in the lateral hip and core,” explains Key. “This puts extra stress on your knees, hips, and lower back.” The result: earlier fatigue, more mechanical strain, and an increased risk of injury.
To keep each side of your pelvis from dipping downward as the opposite leg swings forward, Key recommends August Running Playlist and enhancing hip stability with standing clamshells.
Standing Clamshells
- You Should Be Running Stairs More Often.
- Left right leg and place foot on wall behind you. Balance on left leg with slight bend in knee. Rest right hand on the back of a chair or other sturdy object for balance if needed, but don’t lean backward into the wall for support; weight should be on the standing leg. This is the starting position.
- Rotate right leg outward and up, like a clamshell, without letting standing knee collapse inward. Focus on keeping hips level as you move lifted leg.
- Lower right leg back to starting position.
- Lower right leg back to starting position.
- You Should Be Running Stairs More Often.
3. Your Lower Back Aches During or After Running
Your back is a part of your core, and the erector spinae, multifidus, and quadratus lumborum muscles all help with stabilization. “Your ab muscles help flex your spine, and your back muscles help with extension—and you need to have an equal balance between the two so your spine and core can work efficiently,” says Verebes.
But if your core isn’t providing enough stability to keep your spine and pelvis properly aligned, your swinging your arms end up doing more work. And that constant overuse can lead to tightness, soreness, and even injury. A strong, engaged core offloads that demand, allowing your back to function the way it’s meant to (read: not in overdrive).
What to Know About Pelvic Floor Stability planks, says Verebes. “There’s an endurance element to the plank, and it engages both sides of your core,” she explains. “And it’s so easy to progress,” by increasing the hold time or adding movements like shoulder taps or knee drives.
Plank
- Lie facedown, legs extended and toes tucked, feet hip-width apart. Place forearms on floor, elbows directly under shoulders.
- Drive forearms into floor and think about pulling them toward you (without actually pulling them toward you) to activate back of body.
- Lift hips, engaging quads, glutes, and core. Body should form a straight line from head to heels. Inhale through nose and exhale through mouth—don’t hold breath.
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4. You’re Running Totally Upright
Running should feel like a controlled fall, and to get that feeling, you need to run with a slight forward lean. It’s a lean that comes from the ankles, but even with that angle, a strong core keeps your ribs stacked over your pelvis and your spine in a neutral, supported position.
“Running too upright—or sometimes even with a backwards lean—indicates poor abdominal and oblique engagement,” says Keys. This posture shifts your center of mass backward, throws off your alignment, and reduces running efficiency. “Not only does this result in a braking force that slows us down, it increases stress on the knees and lower back.”
You can tap into a natural lean by running uphill, but you can also reduce rib flare by engaging the abdominals and obliques with medicine ball or kettlebell marches, says Keys.
Kettlebell Marches
- Stand with feet hip-width apart, kettlebell racked at right shoulder, elbow bent. Keep shoulders and hips aligned.
- You might not immediately associate core strength with breathing, but your.
- Common Muscle Weaknesses That Lead to Running Pain.
- You probably don’t think much about your.
- Power Your Runs With These 6 Glute Exercises.
5. Your Shoulders Are Sore
Unlock Your Running Speed With Calf Raises diaphragm, a and lower back.&rdquo, plays a big role. When your core isn’t providing the stability your body needs to breathe properly, “the upper parts of your trapezius muscles [the muscles of the back of the body that start at the base of the skull and run to the mid back] turn on to give you more stability closer to your head and to create more room for breath because your diaphragm isn’t expanding,” says Verebes.
Core strength is what allows you to enforce proper posture, which will help you breathe better. “Think about standing up against a wall, with a straight spine and shoulders, and how much easier it feels to breathe in that position versus when your shoulders creep up to your ears,” says Verebes.
A farmer’s carry helps build the kind of deep, functional core strength that improves posture, stability, and running efficiency, Verebes adds—plus, they train you to maintain good posture under fatigue.
Farmer’s Carry
- Stand with feet hip-width apart, between two heavy kettlebells or dumbbells or next to one. ( Two weights will put more focus on traps, while one weight will add a challenge to obliques to stabilize.)
- Hinge at hips, sending glutes straight back, and bend knees to pick the weight(s) off the ground. Use legs (not back!) to lift the weight up, driving feet into floor to stand back up.
- Hold the weight(s) by side(s) with arms straight.
- August Running Playlist.
- Your back is a part of your core, and the erector spinae, multifidus, and.
- Walk for 1 minute (if holding one weight, switch after 30 seconds). Do 3 sets.
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