Legs · Machine

Leg Extension

How to do the leg extension, the muscles it works, and the mistakes to avoid. Pulled straight from the Kovo app's exercise library.

Illustration of the Leg Extension starting position
Equipment
Machine
Difficulty
Beginner
Logged as
Weighted reps
Movement
Extension
Mechanic
Isolation

See it in motion

Animated demonstration of the Leg Extension

How to do it

Sit on a leg extension machine with your back against the backrest and the front of your ankles against the padded roller. Grasp the handles on the sides for stability. Extend your legs to lift the weight until your legs are almost straight, then slowly lower the weight back to the starting position.

  1. 1Sit back in the leg extension machine and extend your knees to lift the pad; you should feel your quadriceps contracting strongly
  2. 2Pause at the top and squeeze, then lower slowly to feel a stretch
  3. 3Keep your back against the pad and toes relaxed

Common mistakes

  • Don't lock your knees abruptly at the top, maintain control
  • Avoid leaning back or arching your lower back
  • Don't use momentum or swing the weight up, focus on the muscle contraction

Muscles worked

The leg extension mainly works the quads.

  • QuadsPrimary
  • GlutesMinor
  • HamstringsMinor
  • CalvesMinor

Kovo programs the leg extension for you and tracks it every session.

The AI builds your whole program, drops the right lifts into each workout, and adjusts your weights as you get stronger. Free on iOS and Android.

More quads exercises

See all quads exercises →

Last reviewed April 2026.