Leg Extension
A seated machine that isolates the quads, including the rectus femoris which squats load less. Easy to learn and useful for targeted quad volume.
Muscle activation
- Quads100%
Approximate share of work; varies with grip, stance and tempo.
Step by step
1. Start position
Adjust the back pad so your knees line up with the machine's pivot point.
2. Mid-rep
Squeeze the quads hard for a moment at the top.
3. End of the movement
Lower under control to around 90° knee bend or slightly deeper.
4. Common mistake
Kicking the weight up with momentum
Ways to do it
Quad isolation on 2 different setups — pick whatever is free in your gym. Progress is tracked separately for each.
How to do it
Setup
- 1Adjust the back pad so your knees line up with the machine's pivot point.
- 2Set the ankle pad just above your ankles, on the lower shin.
- 3Sit back and hold the side handles to keep your hips down.
Execution
- 1Extend the knees until the legs are straight.
- 2Squeeze the quads hard for a moment at the top.
- 3Lower under control to around 90° knee bend or slightly deeper.
- 4Keep your hips and back in contact with the seat throughout.
Breathing
Breathe out as you extend, breathe in as you lower.
Tempo
3-0-1-1 (eccentric-pause-concentric-pause)
Muscles worked
Primary
Quads
Key form cues
- Knees on the pivot
- Squeeze at the top
- Slow lower
- Hips stay down
Common mistakes
Kicking the weight up with momentum
Lift smoothly and hold the top for a second.
Hips lifting off the seat
Pull down on the handles and reduce the load.
Knee misaligned with the pivot
Adjust the back pad so the knee joint sits in line with the machine's axis.
Range of motion
From about 90° of knee bend to full extension.
Variations
Easier
Single-leg extension with light load
Harder
Leg extension with 2 s top hold
At home
Band leg extension or sissy squat
Machine / cable
Single-leg machine extension