Low Back Pain When Running — Why It Happens & How to Fix It

Dr. Matt
Dec 16, 2025
4 min read

Low Back Pain When Running Is More Common Than You Think

Most runners expect knee pain, hip pain, or Achilles issues…but low back pain when running can be just as disruptive—and it tends to show up in a sneaky way:

You feel fine at first…
Then the back tightens at mile 2–4
Or it hits you later that day (or the next morning)
And suddenly your training plan starts falling apart

A lot of people assume it’s:

“tight hamstrings”
“my back is weak”
“I need to stretch more”
“I’m just getting older”

But in runners, back pain is often a bracing + mechanics + nerve sensitivity issue—not a simple flexibility problem.

Why Your Low Back Hurts When You Run

1️⃣ Your cadence is too low (overstriding = back load)

If you overstride, you increase braking forces and ground reaction forces through your whole system—including your spine.

This is where your 5–20 rule comes in:

Increase cadence by 5% → decrease ground reaction forces by ~20%

If your cadence is under ~175, bump it 5% for a week and reassess.

Example targets:

160 → 168
170 → 178

You don’t need “perfect form.” You just need less stress per step.

2️⃣ You’re hinging at the low back instead of leaning from the ankles

A small forward lean is normal and efficient. But many runners “lean” by bending through the low back (lumbar extension), especially when tired. That creates:

compression on the joints
overactivity of the erectors
feeling “tight” or “jammed”

Quick cue: Think “ribcage stacked over pelvis” and a slight lean from the ankles—not from your waist.

If you filmed yourself from the side, you’d usually see:

ribs flaring up
belly relaxed
stride reaching forward
back doing too much

3️⃣ Your core isn’t bracing the way you think it is

This is a big one. Most runners think bracing means “suck in your stomach.” But bracing is actually:

gentle pressure 360° around your trunk
ribs down
pelvis neutral
breathing without losing control

If the trunk isn’t stable, the spine becomes the stabilizer and takes on more of the stress rather than dispersing it to the muscles.

Test: On a run, brace just enough to reduce your pain by 30–50%. If your pain improves quickly, the back is likely being overloaded by poor trunk control—not a “disc problem.”

4️⃣ Sciatic nerve sensitivity (yes, even without leg pain)

This surprises people. You can have a sensitive sciatic nerve that presents as:

back tightness
glute discomfort
hamstring “tightness”
stiffness after running

Test: Lay flat on your back. Keeping your knee fully extended throughout, lift one leg up in the air while keeping the other completely flat on the ground. Lift until you feel a good amount of stretch. Then, keeping your leg at that spot, lift your chin away from your chest (like you are looking up if you were standing). If the tension in your leg either increases or decreases, you likely have some sciatic nerve sensitivity (yes, even if you don’t have shooting pain down the leg...)

The Fix:

30 sciatic nerve mobilizations per side before running

The goal isn’t to stretch the nerve aggressively, but rather to get it to move back and forth like if you were "flossing" your teeth. It’s to gently desensitize it so your system doesn’t flare during impact.

5️⃣ Under-recovery is the silent driver

Many runners get injured not from overtraining… but under-recovering.

If you’re:

sleeping <7 hours
doing high intensity runs + lifting + long runs
not eating enough
carrying high stress

…your spine and tissues become more irritable. Back pain is often your warning light.

Test: monitor your heart rate variability (best option) or your resting heart rate. Watch for significant fluctuations in these metrics to better understand when your body is asking for a rest!

The Warm-Up That Helps Low Back Pain Fast (Presynaptic Potentiation)

Most runners skip warmups or do toe touches. Instead, you want to activate:

core
glutes
calves
feet

Try this 5–8 minute sequence:

Elbow plank with leg lifts — 2×6–8/side
Side plank with leg lifts — 2×6–8/side
Bent-knee calf raises — 2×15
Standing arch raises — 2×10–12
Band-resisted clamshells — 2×15/side

This “turns on” the system so your back doesn’t have to be the stabilizer.

Quick Fixes You Can Try This Week

✅ 1. Increase cadence by 5%

Most impactful change.

✅ 2. Brace just enough to reduce pain

Maintain that “level of brace” throughout the run.

✅ 3. Do sciatic nerve glides before running

30 reps each side.

✅ 4. Get off the treadmill (if possible)

Many runners notice treadmill mechanics flare the back due to braking and posture. Obviously this is challenging in the MN winter...

✅ 5. Add two weekly strength sessions

The goal isn’t “abs.” It’s trunk stiffness + hip power:

deadlifts or RDLs (slow eccentrics)
split squats
loaded carries
anti-rotation presses

What Doesn’t Work Long-Term

🚫 stretching your hamstrings forever

🚫 foam rolling your back

🚫 taking a week off every time it flares

🚫 only doing “core” exercises that don’t transfer to running

🚫 being told “you just have a bad back”

How Thrive HQ Helps Runners With Low Back Pain

At Thrive HQ, we start with a Pain Diagnostic Session where we:

assess hip mobility + pelvic control
evaluate trunk bracing under load
check nerve sensitivity (sciatic)
analyze cadence, stride, posture
identify the specific trigger (speed, hills, treadmill, fatigue)

Then we build a simple plan that allows you to keep training while resolving the root cause.

🎯 Book a Free Discovery Call and speak with a physical therapist on our team about what pain you are experiencing and see if physical therapy could help you get back to running pain free

🚀 Join the Pain-Free Runner Challenge (FREE Beta – 20 spots)

If you want a full system for running pain—not just one-off tips—we’re launching our Pain-Free Runner Challenge in early 2026.

The first cohort is a FREE beta group (limited to 10 runners).

👉 Join the early access list here: https://visit.thrive-hq.com/pain-free-runner-challenge