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Strength Training · Bodybuilding

Leg Extension

The leg extension is a seated machine exercise that trains the front of your thighs by straightening your knees against resistance.

  • Beginner
  • Isolation
  • Low injury risk
  • Rest 1 min
Video by Jeff Nippard on YouTube

How to do it

  1. Adjust the seat so your knees line up with the machine’s pivot when your back rests against the back pad.
  2. Position the roller across your lower shins, just above your ankles.
  3. Set the starting position with your knees comfortably bent.
  4. Grip the handles beside the seat.
  5. Straighten both knees to lift the roller.
  6. Bend your knees to return to the starting position.

Form cues

  • Keep your hips planted.
  • Move both legs evenly.
  • Exhale as you lift.

Common mistakes

  • Kicking the weight upUse a weight you can lift smoothly without swinging your torso.
  • Dropping the weightTake about two seconds to lower the roller without letting the stack slam.
  • Stopping every rep halfwayUse your full comfortable range rather than shortening the movement to lift more weight.

Safety

Excessive resistance or an unsuitable machine setup can aggravate your knees. Snapping into the top position can also stress the joint, especially as you tire.

  • Check that all adjustment pins are fully engaged before starting.
  • Try a light warm-up set to check the machine fit.
  • Finish each extension without forcefully snapping your knees straight.
  • Stop the set if you feel sharp or increasing knee pain.

If you have an ongoing knee problem or recent knee surgery, ask a physiotherapist or doctor about an appropriate load and movement range first.

Muscles worked

Front

Primary muscles

  • Quadriceps

Equipment

  • Leg Extension Machine

Sets and reps

Sets
2–3
Target
10–15 reps
Rest
1 min

Finish each set feeling you could complete about two more controlled reps.

Workout plans with Leg Extension

Build muscle · intermediate

4-Day Upper Lower Workout Plan for Men Over 50

This muscle-building plan gives men over 50 a structured upper lower routine across 4 training days. Barbell lifts anchor the sessions, with dumbbell, cable and machine work alongside walking or cycling. It offers a clear schedule for lifters with intermediate training experience.

4 days / week · 60 min estimated · Barbell Collar, Olympic Flat Bench, Powerlifting Barbell, Weight Plate, Adjustable Bench, Dumbbell, Upright Utility Bench, Lat Pulldown Bar, Lat Pulldown Machine, Cable Column, Cable Rope Attachment, Treadmill, Power Rack, Rack Safety Supports, Barbell, Standing Calf Raise Machine, Exercise Mat, Upright Exercise Bike, Close-Grip Row Handle, Lat Pulldown / Low Row Station, Chest Press Machine, Leg Extension Machine, Seated Leg Curl Machine, Seated Calf Raise MachineExplore the plan