Leg Extension

A machine isolation exercise targeting the quadriceps. Useful for adding direct knee-extension volume without loading the hips or spine heavily.

Also known as: leg extensions, leg extension machine, quad extensions, leg ext, quads machine

Beginner Isolation Leg extension machine

How to do the Leg Extension

Adjust the seat so your knees line up with the machine's pivot point.
Sit back against the pad and place your shins behind the lower roller.
Grip the handles and start with knees bent comfortably under the pad.
Extend your knees until your legs are nearly straight and quads fully shortened.
Squeeze the quadriceps briefly at the top without kicking or snapping the weight up.
Lower the pad back down until your knees are bent and the stack stays controlled.

Common mistakes

Knees set forward of pivot
Kicking the weight upward
Hips lifting off seat
Stopping short of top range
Letting the stack slam down

Form cues

Align knees with pivot
Stay glued to pad
Lead with the shins
Squeeze the top

Muscle activation

Primary Secondary

Quads 10

Relative activation, 0–10, from the seto exercise database.

Programming

Goal	Sets × reps	Rest	RPE
Muscle growth A	3–4 × 8–12	75s	8
Endurance B	2–3 × 15–20	45s	6.5

How to read: 4–5 × 3–6 means 4–5 sets of 3–6 reps. Rest is the pause between sets. RPE is effort on a 1–10 scale — 8 means you could do about 2 more reps.