Machine Single-Leg Leg Extension
A unilateral machine exercise isolating the quadriceps to build strength, enhance definition, and correct leg imbalances; supports knee stability and hypertrophy goals.
About Exercise
Equipment
Leg Extension Machine
Difficulty
2/5 • Beginner
Primary Muscle Groups
Quads
Secondary Muscles
Hip Flexors, Abs
Popularity Score
6
Goals
Training Style
Setup Requirements
Requires Rack
No
Requires Bench
No
Requires Spotter
No
Space Needed
Small
Noise Level
Low
Muscle Breakdown
View Muscle MapQuads
10/10Rectus Femoris, Vastus Lateralis, Vastus Medialis
Hip Flexors
3/10Iliopsoas
Abs
3/10Transverse Abdominis
Programming
Typical Rep Range
10-15 reps
Rest Between Sets
60-90 seconds
How to Perform
Sit on the leg extension machine with back against the pad. Adjust the seat so knees align with the pivot point and the ankle pad rests above your ankles. Grasp handles for stability.
- Exhale and extend one leg by contracting your quadriceps, pushing the pad upward.
- Pause briefly at the top and squeeze your quads.
- Inhale and slowly lower the pad back to the starting 90-degree knee bend.
- Maintain control without letting the weight stack touch down.
- Switch legs after completing reps on one side.
Coaching Tips
Form Cues
- Knees track over toes
- Squeeze quads at top
- Keep back against pad
- Control the descent
Breathing
Inhale during the lowering phase and exhale as you extend your leg, bracing your core throughout.
Tempo
3-1-1
Range of Motion
Extend from 90-degree knee flexion to near full extension with a slight bend at the knee, avoiding lockout.
Safety
Safety Notes
- Avoid if you have acute knee pain or ligament issues
- Do not lock knees to prevent joint strain
- Start with light weight to master form
- Consult a professional for pre-existing knee conditions
Spotting
Spotting not required; use machine's pin-loaded safeties for controlled drops.
Common Mistakes
- Swinging legs with momentum
- Locking knees at top
- Arching lower back
- Using excessive weight leading to poor form
When to Avoid
- Acute knee injuries
- Knee ligament instability
- Patellar tendonitis
Flexibility Needed
- Adequate knee flexion to 90 degrees
Build Up First
- Familiarity with machine adjustments
- Basic quad activation awareness
Also known as
Single-Leg Machine Leg Extension, Unilateral Leg Extension
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