Deep dive · series 1 · 9 cues
Low-impact running
A typical S-shaped spine flexes a little on every landing and soaks up some of the shock. A flat back has less curve to give, so more of each landing reaches the lower back. My answer: let the legs be the spring, and land softly enough that the spine has less to do.
The skeleton reels are illustrations, slowed down and exaggerated. They’re not medical advice. If running hurts, see a physio.
START HERE
Why a flat back needs a different plan
The S-curve can flex on landing. A flat back has little curve to flex, so the shock that a curve would absorb travels up towards L5/S1, the lowest joint in the lower back.
Evidence: in Castillo’s 2017 Harvard thesis, the size of the lower-back curve made no difference to shock absorption when walking, but a strong difference when running.
CUE 01
The forefoot spring
- Land on the ball of the foot, knees soft.
- Let the heel lower: the calf and quads take the load.
- Spring off: the Achilles recoils and the glutes drive.
Why: the calf and Achilles are built to store and return energy, so they can do the work the spine’s curve would otherwise do.
CUE 02
Land under your hips
- Overstriding: the heel lands well ahead with the knee almost straight, and the jolt runs up to L5/S1.
- Instead: the ball of the foot lands under you, the knee is soft and the legs soak it up.
Why: a foot that lands under the body lets the knee and ankle bend to absorb the landing. A foot that lands far ahead brakes against a straight leg.
CUE 03
Quicker steps
- Same speed, slightly shorter, quicker steps (in the reel: 155 → 170 steps a minute).
- Less up and down, softer landings.
Evidence: in 45 recreational runners, raising step rate by 5–10% reduced vertical bounce and the energy absorbed at the knee (Heiderscheit et al. 2011).
CUE 04
The calf is your damper
- Stuck on your toes: a stiff ankle, a strained calf, less give on landing.
- Let the heel lower under control, so the ankle acts as a damper.
Why: a forefoot landing only helps if the ankle is allowed to give. Locking the heel up turns the spring into a stiff post.
CUE 05
Run forward, not up
- Bouncing: big ups and downs, further to drop, harder landings.
- Gliding: a small, flat wave and a shorter drop.
Evidence: in 20 runners, simply cueing less bounce lowered loading rates and peak impact force, more strongly than raising cadence did (Adams et al. 2018).
CUE 06
Lean from the ankles
- Not folded at the waist, with chest and eyes down.
- A tall, slight tilt from the ankles: chin up, eyes to the horizon, head to heel in one line.
Evidence: in 23 runners, more forward bend at the trunk raised loading rate by 29%, the landing impact peak by 20% and hip extensor effort by 70% (Warrener et al. 2021).
CUE 07
Light brace, steady breath
- Switch the core on lightly, not a sit-up squeeze.
- Breathe into the belly, sides and back, in two steps and out two steps.
Evidence: a computer model built from 8 runners found that weak deep core muscles raised loading on the lower spine by up to about 15% (Raabe & Chaudhari 2018, Journal of Biomechanics). A model, not a trial.
CUE 08
Let the arms swing
- Holding the arms still makes the pelvis and trunk twist more to balance the legs.
- Relaxed arms swing opposite the legs and cancel that twist.
Evidence: 13 runners used 3–13% more energy when their arms were held still, and their upper body twisted more (Arellano & Kram 2014).
CUE 09 · BACK TO CUE 01
Push back with the hips
- Pushing with the back: short leg drive, the pelvis tips forward and the lower back arches.
- Pushing with the hips: the leg drives back, the glutes do the work and the pelvis stays level.
- Feel it: a stretch at the front of the hip and the glute switching on as you push off.
Evidence: in 14 runners, less hip extension went with more forward pelvic tilt while running (Schache et al. 2000). A link, not proof of cause.
A work in progress
These cues are what I’m working on, not a guarantee, and change your running a little at a time. If you have back pain or leg symptoms, get a physio to look at your running before you change it.