Hip Hinge · Intermediate

45-Degree Back Extension

Compound hip hinge exercise using machine.

45-Degree Back Extension demonstration (no audio).

Movement pattern: Hip Hinge
Difficulty: Intermediate
Equipment: Machine
Mechanics: Compound
Sides: Bilateral
Main plane: Sagittal

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How to do the 45-Degree Back Extension

Cues reviewed by Kwabena Osei on 20 Sep 2026

Setup

Hips resting on the pad, ankles secured, body angled roughly 45 degrees, hands crossed at your chest or lightly touching your temples.

Lower your torso down by hinging at the hips, keeping your spine's natural S-shaped curve throughout -- never let your back round into a C-shape.
Raise back up to a straight line from head to heels by extending your hips and lower back, stopping at neutral rather than hyperextending past it.

Common mistakes

Rounding the spine into a C-shape at the bottom instead of maintaining its natural curves -- the erector spinae runs the full length of the back, and a rounded posture loads it incorrectly.
Hyperextending well past a straight line at the top, adding unnecessary lumbar compression instead of stopping at neutral.

Muscles worked

Primary

Secondary

How the knowledge graph models this movement

Each joint action, with the role and emphasis the graph assigns each muscle. These are qualitative anatomical labels, not measured muscle activation.

Hip extensionprimary action
Gluteus maximus (prime mover, high emphasis); Gluteus maximus (prime mover, high emphasis); Biceps femoris long head (prime mover, high emphasis); Semitendinosus (synergist, high emphasis); Semimembranosus (synergist, high emphasis); Adductor magnus (synergist, moderate emphasis)
Spine extensionprimary action
Erector spinae (prime mover, high emphasis); Multifidus (synergist, moderate emphasis); Quadratus lumborum (synergist, moderate emphasis)

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From the Knowledge Library

Educational content only — not medical advice. Consult a qualified professional for individual guidance, especially around injury, pregnancy or medical conditions.