Exercise guide · Legs & Glutes

Machine Leg Extension

Leg extension isolates the quadriceps on a seated machine. A pad rests on your shins and you extend your knees to lift the stack. It is commonly used after compound leg work to target the front of the thighs.

Targets: Quads
Equipment: Machine
Type: Isolation

Step by step

How to do the Machine Leg Extension

Adjust the seat so the pivot point aligns with your knee joint and the shin pad sits just above your ankles.
Select a moderate weight. Sit with back against the pad, grip the handles, and place ankles under the lower shin pad.
Start with knees bent at about 90 degrees. Keep hips and back firmly on the seat.
Extend knees smoothly until legs are straight but not hyperextended or snapped locked.
Pause briefly at the top, then lower under control to the start without letting the weight slam.

Form cues

Only your lower legs move
Squeeze quads at full extension
Toes point up or slightly forward—don't twist ankles
Slow on the way down

Common mistakes

Lifting hips off the seat to help the weight up
Swinging or using momentum at the bottom
Using too heavy a weight and shortening range
Locking knees aggressively every rep

Muscles worked

Primary

Quads

Secondary

None significant

Safety: Use moderate weight and controlled reps. Reduce load if you feel sharp pain at the front of the knee.

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