Single-Leg Leg Extension

A beginner isolation strength exercise that works the quads, using a machine.

Single-Leg Leg Extension — Starting position Starting position
Single-Leg Leg Extension — End position End position
Difficulty Beginner
Type Strength
Equipment Machines
Primary Muscle Quads
AI Rep Counting Log manually

How to Do Single-Leg Leg Extension

  1. Seat yourself in the machine and adjust it so that you are positioned properly. The pad should be against the lower part of the shin but not in contact with the ankle. Adjust the seat so that the pivot point is in line with your knee. Select a weight appropriate for your abilities.
  2. Maintaining good posture, fully extend one leg, pausing at the top of the motion.
  3. Return to the starting position without letting the weight stop, keeping tension on the muscle.
  4. Repeat for the desired number of repetitions.

Muscles Worked

Front

Primary

Where Single-Leg Leg Extension does most of its work.

Alternatives to Single-Leg Leg Extension

10 movements that train the same primary muscle, closest substitutes first — same kind of training, then variations of the movement itself, then a similar difficulty.

  1. 1 Single-Leg High Box Squat

    Single-Leg High Box Squat

    A beginner compound strength exercise that works the quads.

    beginner Not specified
  2. 2 Leg Extensions

    Leg Extensions

    A beginner isolation strength exercise that works the quads, using a machine.

    beginner Machines
  3. 3 Leg Press

    Leg Press

    A beginner compound strength exercise that works the quads, using a machine.

    beginner Machines
  4. 4 Smith Single-Leg Split Squat

    Smith Single-Leg Split Squat

    A beginner compound strength exercise that works the quads, using a machine.

    beginner Machines
  5. 5 Leg Raises

    Leg Raises

    Leg raises target the often-neglected lower portion of the abdominals and hip flexors. They're one of the most effective exercises for building lower ab strength and definition.

    intermediate No Equipment
  6. 6 One Leg Barbell Squat

    One Leg Barbell Squat

    An advanced compound strength exercise that works the quads, using a barbell.

    advanced Barbell
  7. 7 Squats

    Squats

    The squat is the king of lower body exercises, targeting the quadriceps, glutes, and hamstrings while building core stability. It's a fundamental movement pattern that translates directly to everyday activities.

    beginner No Equipment AI tracked
  8. 8 Barbell Side Split Squat

    Barbell Side Split Squat

    A beginner compound strength exercise that works the quads, using a barbell.

    beginner Barbell
  9. 9 Barbell Squat

    Barbell Squat

    A beginner compound strength exercise that works the quads, using a barbell.

    beginner Barbell
  10. 10 Barbell Walking Lunge

    Barbell Walking Lunge

    A beginner compound strength exercise that works the quads, using a barbell.

    beginner Barbell

Frequently Asked Questions

What muscles do single-leg leg extension work?

Single-Leg Leg Extension primarily works the quads.

What equipment do I need for single-leg leg extension?

Single-Leg Leg Extension uses machines.

Single-Leg Leg Extension: is it suitable for beginners?

Yes. Single-Leg Leg Extension is rated beginner. Movements you can learn in a session, with a low skill floor and a forgiving failure mode.

What can I do instead of single-leg leg extension?

Single-Leg High Box Squat, Leg Extensions, Leg Press train the same primary muscles and are listed with 7 more alternatives above.

Can Fitnit count my single-leg leg extension reps automatically?

Not automatically yet. Fitnit's AI rep counting covers push-ups, squats, dumbbell curls, crunches and pull-ups today; single-leg leg extension can be logged manually in the app, and tracked movements are added over time.

Photographs and step-by-step instructions from free-exercise-db, a public-domain exercise dataset. Muscle mapping and alternatives by Fitnit.

Track Your Single-Leg Leg Extension with AI

Fitnit automatically tracks push-ups, crunches, squats, pull-ups, and curls with advanced body tracking technology — and you can manually input any other workout too. Start free — Pro is $8.99/month.