Core Exercises for Better Running Posture: A Physiotherapist's Honest Guide

Somewhere around kilometre 40 of a mountain ultra, nobody's posture looks like the race photos from kilometre 5. The chest caves, the pelvis tips forward, the arms start crossing the midline, and suddenly every stride costs more than it should. I've watched it happen to runners around me on courses across Europe, and I've felt it happen in my own body — that moment when the trunk stops doing its job and the legs have to pay the bill.

Here's what I want you to understand before we get to a single exercise: the muscles that hold your running posture together late in a race are almost never the ones people train when they say they're "doing core." Sit-ups and crunches build a muscle that flexes your spine forward — the exact opposite of what a tired runner needs. What you actually need is the deep system: transverse abdominis, obliques, glute medius, and the small spinal erectors that keep you stacked over your pelvis for hours at a time.

As a physiotherapist and an ultra trail runner, I use six exercises for this — on myself, and with the runners who come to my callanetics classes asking why their lower back aches after long runs. This is the honest version of that conversation.

Why "Core" for Runners Means Something Different

Running is a series of single-leg landings. Roughly 180 times per minute, one leg accepts your full body weight (plus impact forces) while the other swings through. During that split second on one leg, three things have to happen simultaneously:

Your pelvis has to stay level. If your glute medius on the stance side is weak or slow, the opposite hip drops. That hip drop travels down the chain and shows up as knee pain, IT band irritation, and a collapsing arch.

Your trunk has to resist rotation. Your swinging arm and leg create rotational force with every stride. Your obliques and transverse abdominis are supposed to absorb it. When they can't, your torso twists, your arms cross your body, and you leak energy sideways instead of moving forward.

Your spine has to stay tall under fatigue. The deep spinal erectors are endurance muscles. When they give out at hour three, you fold at the waist, your stride shortens, and your breathing gets compressed.

Notice that none of these three jobs involves flexing the spine — which is all a crunch trains. Running core work is anti-movement work: anti-rotation, anti-lateral-flexion, anti-extension. You're training muscles to hold a position while your limbs try to pull you out of it. That is precisely what happens on the run.

There's another benefit worth mentioning: a stable trunk gives your hips a fixed anchor to pull against. Runners who fix their core stability often find their stride mechanics improve almost by accident — the same reason I always pair core work with form retraining when someone is working on correcting an overstriding pattern.

The Six Exercises I Actually Use and Prescribe

I've filtered hundreds of core exercises down to these six because they cover the three anti-movement jobs, they need almost no equipment, and they translate directly to what you feel on the trail. For each one, I'll tell you what good form looks like, what runners typically get wrong, and what it fixes in your running.

1. Dead Bug — the foundation of deep core activation

How to do it: Lie on your back, arms reaching to the ceiling, hips and knees bent at 90 degrees. Exhale and press your lower back gently into the floor — not by squeezing your glutes, but by drawing your lower ribs down toward your pelvis. Now slowly extend your right arm overhead and your left leg out long, hovering above the floor. Return. Switch sides. Six to eight slow reps per side.

What good looks like: Your lower back stays in quiet contact with the floor the entire time. The movement is slow enough that you could stop at any point. You breathe throughout.

What runners get wrong: Two things, almost universally. First, rib flare — the ribs pop up toward the ceiling as the arm goes overhead, which means the transverse abdominis has switched off and the back is arching. Second, breath holding. If you're holding your breath to stay stable, you're using pressure instead of muscle, and that strategy fails the moment you're breathing hard at threshold pace. If you can't keep the back flat, shorten the lever: extend the leg with a bent knee, heel skimming the floor.

What it fixes on the run: That deep "corseted" feeling of running tall while breathing hard. The dead bug teaches your trunk to stay stable while your limbs move in opposition — which is, mechanically, exactly what running is.

2. Bird Dog — spinal endurance with a moving base

How to do it: On hands and knees, hands under shoulders, knees under hips. Extend your right arm and left leg until they're in line with your torso. Pause for two full breaths. Return without letting your hips sway. Six reps per side, slow.

What good looks like: If someone placed a cup of water on your lower back, it wouldn't spill. The extended leg reaches long rather than high — height comes from hip extension, not from arching the lumbar spine.

What runners get wrong: They kick the leg up too high and hinge through the lower back, turning a stability exercise into a back-arching one. The other error is rushing. A fast bird dog trains momentum; a slow one with a two-breath pause trains the deep spinal erectors that keep you upright at kilometre 40. Slow is the entire point.

What it fixes on the run: Late-race trunk endurance. This is the exercise for runners who tell me their lower back is the first thing to complain on long runs.

3. Side Plank with Hip Lift — the glute med builder

How to do it: Lie on your side, elbow under shoulder, feet stacked (or knees bent for an easier version). Lift your hips into a straight line from head to feet. Then lower the hips a few centimetres and lift back up — 8 to 12 controlled lifts per side.

What good looks like: Your body is one straight line viewed from the front — no sagging hips, no piking at the waist. You should feel the work in the side of the hip and the waist of the bottom side, not in your shoulder.

What runners get wrong: They sag through the middle and hang on the shoulder joint, or they rotate the top hip backward to make it easier. Both cheat the glute medius out of its job. Keep the top hip stacked directly over the bottom one.

What it fixes on the run: Hip drop. This is the number one exercise I give runners with lateral knee pain or that telltale swaying gait in race photos. If your pelvis dips toward the swing leg with every stride, the side plank with hip lift is where you start. Static side planks are fine; the hip lift version is better, because running is dynamic and your glute med needs to fire and re-fire, not just hold.

4. Pallof Press — pure anti-rotation

How to do it: Anchor a resistance band at chest height. Stand side-on to the anchor, holding the band with both hands at your sternum. Press your hands straight out in front of you, pause three seconds, and return. The band is trying to twist you toward the anchor; your job is to not let it. Eight to ten reps per side.

What good looks like: Nothing moves except your arms. Hips and shoulders stay square to the front. Ribs stay down, breath keeps flowing.

What runners get wrong: They stand too close to the anchor (no challenge) or too far (they lean away and turn it into a whole-body counterweight trick). You want tension you can resist with your trunk, not your bodyweight. And again: breathing. If your exhale stops, drop the resistance.

What it fixes on the run: Energy leaks. Every arm swing tries to rotate your torso; the Pallof press trains your obliques to cancel that rotation so the force goes into forward motion. Runners whose arms cross their midline — you can see it in any race photo — almost always test weak here. To make it even more running-specific, do it standing on one leg.

5. Standing Single-Leg Reach — balance meets posture

How to do it: Stand on one leg with a soft knee. Hinge at the hip and reach both hands forward and slightly down, letting your free leg extend behind you, then return to tall standing. Keep your spine long throughout — this is a hip hinge, not a back bend. Eight reps per side.

What good looks like: Your pelvis stays level (imagine headlights on your hip bones pointing at the floor evenly). The movement is smooth, and you finish each rep fully tall — squeezing the standing-leg glute at the top.

What runners get wrong: The pelvis rotates open as they reach, the standing knee wobbles inward, and the spine rounds. If you're wobbling wildly, shorten the reach. Quality of control matters far more than range.

What it fixes on the run: This is the closest exercise on the list to actual running — single-leg stance, hip loading, trunk control, all at once. It sharpens the split-second stability you need every time your foot lands on an uneven trail. My orienteering background biases me here, I admit: when you're reading a map at speed through Bulgarian forest, your ankles and hips make hundreds of micro-corrections per minute, and this exercise is the gym version of that skill.

6. Loaded Carry — posture under fatigue

How to do it: Pick up a heavy kettlebell, dumbbell, or even a loaded shopping bag in one hand. Walk 30 to 40 metres, tall, without leaning away from the weight. Switch hands and walk back. Two to three lengths per side.

What good looks like: Someone watching from behind can't tell which hand holds the weight. Shoulders level, ribs stacked over pelvis, smooth even steps.

What runners get wrong: They lean away from the load, hike the opposite shoulder up to their ear, or shuffle with tiny tense steps. Choose a weight heavy enough that you feel your obliques working, but light enough that you can walk normally.

What it fixes on the run: Everything at once, honestly. The suitcase carry is anti-lateral-flexion under fatigue while walking — the closest thing in a gym to "hold your posture together in the last 10K." I did carries religiously in the block before my last long mountain race, and the difference showed up exactly where I expected: my form at hour six looked like my form at hour two. My kids think it's hilarious watching me pace the hallway with a kettlebell, but it's the least glamorous exercise on this list and possibly the most valuable.

The 15-Minute, 3x/Week Template

You don't need an hour. You need consistency and honest form. Here's the exact structure I recommend — run through it as a circuit, resting only as needed:

| Order | Exercise | Dose |
|---|---|---|
| 1 | Dead bug | 6–8 slow reps per side |
| 2 | Bird dog | 6 reps per side, 2-breath pause |
| 3 | Side plank with hip lift | 8–12 lifts per side |
| 4 | Pallof press | 8–10 reps per side |
| 5 | Standing single-leg reach | 8 reps per side |
| 6 | Loaded carry | 2 lengths of 30–40 m per side |

One round takes about 15 minutes. Do it three times a week — ideally after easy runs or on non-running days, never right before a hard session (a pre-fatigued core on speed day is asking for sloppy mechanics). If you already do a short activation routine before long runs, like a pre-run glute and IT band warm-up, keep that separate — activation wakes muscles up; this template builds them.

Progression, in order: first make the reps slower, then add the pauses, then add load (a light dumbbell in the dead bug, a heavier band on the Pallof, more weight in the carry). Only progress when the current version is boring and your form is clean. Boring but sloppy means you're not done yet.

How long until you feel it on the run? Most runners notice something in three to four weeks — usually described as "I stopped collapsing in the last third of my long run" or "my lower back didn't ache afterward." Measurable changes in hip stability take closer to eight to twelve weeks. Core strength is quiet like that: you don't notice it working, you notice everything else complaining less.

The Short Version

Your running posture at kilometre 40 is decided by muscles you train in a quiet room, weeks earlier. Skip the crunches. Train the deep stabilisers to resist rotation, resist hip drop, and hold you tall under fatigue — dead bug, bird dog, side plank with hip lift, Pallof press, single-leg reach, loaded carry. Fifteen minutes, three times a week, with ribs down, pelvis level, and breath flowing. Start this week, keep the reps slow and honest, and give it a month before you judge it. Your last 10K will tell you whether it worked.