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Quads

Single Leg Extension

The Single Leg Extension is a strength exercise on a machine for your quads. Share of the load in the Zulta muscle model: quads (vastus lateralis) 34%, quads (rectus femoris) 30% and quads (vastus medialis) 30%.

Level: BeginnerEquipment: MachineSingle-joint (isolation)Unilateral: one arm or leg at a time

How to do it

  1. Set the leg extension machine so the knee is level with the pivot and the pad sits just above the ankle.
  2. Sit tall with one leg behind the pad and the other leg tucked back or resting beside it.
  3. Extend the working knee until the leg is straight.
  4. Pause and squeeze the front of the thigh at the top.
  5. Lower with control to the start, then switch legs after the set.

Tips

  • Point the toes slightly up to keep the ankle neutral.
  • Hold the handles firmly so the pelvis does not shift.

Common mistakes

  • Leaning back to help the lift.
  • Letting the pad crash down.
  • Setting the pad too low on the foot.

Muscles worked by the Single Leg Extension

  • Quads (vastus lateralis) Primary34%
  • Quads (rectus femoris) Primary30%
  • Quads (vastus medialis) Primary30%
  • Upper abs Stabilizer2%
  • Forearm flexors Stabilizer2%
  • Hip flexors Stabilizer2%

Share per muscle in the Zulta muscle model. The model spreads the load of one rep over 40 muscles, based on EMG and biomechanics research.

Knee extension with the thigh fixed isolates all four quadriceps heads; nothing else moves.

Single Leg Extension alternatives

Same equipment

Different equipment

No equipment

Make it harder

Frequently asked questions

What muscles does the Single Leg Extension work?

Mainly the quads (vastus lateralis), quads (rectus femoris) and quads (vastus medialis).

Is the Single Leg Extension good for beginners?

Yes. The Single Leg Extension is rated beginner in the Zulta library: the technique is easy to learn with a light weight.

What is a good alternative to the Single Leg Extension?

For example the Leg Extension, Leg Extension Single Leg and Sissy Squat Machine. They train mostly the same muscles.

How do you make the Single Leg Extension harder?

Add weight or reps, or move on to the Standing Leg Extension and Reverse Nordic.

Sources

  • Escamilla et al. 1998, MSSE 30(4):556-569 (open vs closed chain)

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