# Leg Extension (Machine)

> A seated machine exercise that straightens the knees to build the quads.

Page: https://fitnessie.app/exercises/leg-extension/
Type: Machine · Isolation
Demo video: https://fitnessie.app/demos/leg-extension-machine/8f0b6150a98d109d.mp4

## How to do it

1. Adjust the seat so your knees line up with the machine's pivot and your back rests on the pad.
2. Set the roller just above your ankles and hold the side handles.
3. Straighten your legs until they are straight or nearly so, without forcing the knees back.
4. Lower slowly until your knees are bent to about a right angle.

## Key cues

- Knees in line with the pivot
- Roller just above the ankles
- Back against the pad, hips down
- Control the way down

## Common mistakes

- Using too much weight and swinging the weight up
- Arching your lower back off the pad
- Stopping short of a full extension
- Hyperextending the knees at the top

## Muscles worked

- Primary: Quads

## Equipment

Leg extension machine.

## Variations

- [Leg Extension (Single Leg)](https://fitnessie.app/exercises/single-leg-extension/)

## Programs that use it

- [PHUL](https://fitnessie.app/programs/phul/)
- [Upper/Lower](https://fitnessie.app/programs/upper-lower/)

## References

- [StrengthLog: Leg Extension](https://www.strengthlog.com/leg-extension/)
- [RitFit: Proper Leg Extension Form](https://www.ritfitsports.com/blogs/article/proper-leg-extension-form)
- [Motra: Leg Extension](https://www.motra.com/exercises/legExtension)