BackPin machineIsolation — spinal extension

Machine Back Extension

Reviewed by Bryan Cortez, MS

Extend the trunk to neutral; do not turn the top into a lean-back contest.

Rep Sweet Spot

10-20

Sets

2-4

sets

RIR

2-3

Canonical coaching profile

Complete coaching guidance, with the evidence boundary visible

This profile is served from the canonical Airtable coaching library. Its theory tier and evidence confidence remain separate source-truth fields.

Theory

Theory tier S

Evidence confidence

Mechanics-led evidence confidence (D)

The tier is a reasoned biomechanics judgment. Evidence grade D is mechanics-led and is not direct hypertrophy proof; the full category evidence-control program remains pending.

Why it ranks: Machine Back Extension is ranked for Spinal erectors because its named path directly expresses loaded spinal extension or anti-flexion under a declared trunk path; external support reduces balance and bracing demands. The main limitation is fit to the exact machine path.
Primary limiter: Machine axis and pad fit; a mismatched setup can shift motion into the hips or create an uncomfortable lumbar path.
Safety and fit: Use a pain-free range, avoid forced end-range hyperextension, and stop if symptoms radiate or worsen rather than treating the set as rehabilitation.
What would change the call: Change the placement if the exact machine geometry removes target torque, restricts usable range, or creates a common joint-fit reversal.

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Demonstration

Demonstration production queue

The written coaching card is ready. The owned video is next.

Physique Skool is filming one canonical demonstration per exercise. Until this movement is published, use the setup, execution, common errors, programming, and substitutions below.

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How to do it

Setup

Align the machine axis with the intended trunk motion
Secure the pelvis and feet
Set the back pad across the upper trunk
Start in a comfortable flexed position

Execution

Extend the trunk through a controlled arc
Finish tall without leaning past neutral
Return slowly to the same start point
Keep the pelvis anchored

Common Errors

Driving with the legs and hips
Bouncing out of the bottom
Hyperextending at the top
Changing pad or seat position between sessions

Cues That Work

Unroll the trunk against the pad; finish tall, not backward; keep the belt line pinned

No-Fly Zone

Avoid maximal loading or forced hyperextension beyond the controlled neutral finish.

Programming

Sequence priority

Flexible

The supported path is repeatable, but direct trunk fatigue can affect later bracing-heavy lifts, so place it after those lifts.

Progression

Model — Double

Fallback model — RPE

Keep pad position and start/finish landmarks fixed; add reps before one pin step and never buy load with extra end-range extension.

Best program fit

Full body

Load increments

Standardone selector-pin step

Smaller incrementadd reps or slow the return

Larger incrementone full increment after the same range is repeatable

If it hurts

Pain is information, not a challenge to push through. Stop the set if pain is sharp, worsening, or changes how you move. These are exercise-selection options, not medical diagnosis or rehabilitation advice.

Work down this list in order. Stop at the first change that removes the pain.

Step 1
Setup tweaks
Adjust seat, pad, and range so the trunk moves without the pelvis sliding.
Step 2
ROM / tempo / bias
Use a three-second return and a brief neutral-position stop.
Step 3
Implement swap
45-degree back extension or bird dog for a lower-load option.

Substitutions

Approved fallback

45-degree back extension or bird dog for a lower-load option.

The Evidence

This provides direct, supported spinal-extension loading. It is not a treatment claim, and the best range depends on machine fit, training history, and symptom response.

SFR — 1.8

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