Single-Leg Extension
Primary
Quadriceps
Secondary
Glutes
Equipment
Machine
Difficulty
Beginner
Type
Push
Single-Leg Extension
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The single-leg extension isolates each quadriceps independently, making it impossible for your dominant leg to compensate for the weaker one. This targeted approach identifies strength imbalances and allows you to correct them with focused training. Use lighter weight than bilateral extensions and focus on matching reps and tempo on each side.
When to use it
Use to address quad imbalances or for focused work.
Who it's for
Anyone wanting to isolate each quad.
Start with your weaker leg and match that performance with your stronger side—do not let the strong side do extra work. The goal is balance, not maximum weight. If one leg consistently falls behind, give it priority.
Single-Leg Extension — targeted muscles
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How do you perform the Single-Leg Extension?
- 1
Sit on the leg extension machine.
- 2
Position one ankle behind the pad.
- 3
Keep your other leg relaxed or off the pad.
- 4
Extend your working leg by straightening the knee.
- 5
Squeeze your quad at the top.
- 6
Lower with control and repeat.
What are the best tips for the Single-Leg Extension?
Use lighter weight than bilateral extensions.
Focus on the quad squeeze.
Control both the lift and lower.
Great for addressing imbalances.
When to Use the Single-Leg Extension
Program single-leg extensions when rehabbing a leg injury, correcting known imbalances, or when one leg visibly lags in development. Use them as a finishing exercise after compound work, or as a warm-up to assess which leg needs extra attention that session.
Common Single-Leg Extension mistakes
Using too much weight.
Loading more weight than you can control on the Single-Leg Extension forces compensatory movement patterns that bypass your Quadriceps. Drop the weight until you can perform every rep with clean form — your results will actually improve.
Swinging or using momentum.
Bouncing or using momentum during the Single-Leg Extension takes work away from your Quadriceps and puts your connective tissue at risk. Control the weight through the full range — if you can't, lower the load.
Not achieving full extension.
Cutting the range of motion short on the Single-Leg Extension means your Quadriceps never reaches full stretch or full contraction. Research shows full range of motion produces significantly more muscle growth than partial reps at the same load.
Rushing through reps.
Rushing through the Single-Leg Extension reduces the time your Quadriceps spends under tension — which is one of the main drivers of growth. Aim for a controlled 2-second lowering phase on every rep.
Single-Leg Extension — who it's best for
Anyone wanting to isolate each quad.
How to Program the Single-Leg Extension
Lower reps with heavier weight builds raw strength. Your muscles and nervous system adapt to handle more load over time. This range is best for strength-focused goals.
This rep range keeps your muscles under tension long enough to trigger growth. Most people see the best muscle-building results in this zone. It balances strength and muscle size.
Higher reps with lighter weight builds muscular endurance and improves conditioning. This range is good for joint health and building work capacity.
General guideline: 3 sets of 12-15 reps per leg. Rest 45-60s.
What are good alternatives to the Single-Leg Extension?
Other Variations
- Pause Single-Leg Extension
- Tempo Single-Leg Extension
Frequently Asked Questions About the Single-Leg Extension
The Single-Leg Extension primarily targets the Quadriceps, making it an effective exercise for quadriceps development. Secondary muscles worked during the Single-Leg Extension include Hip stabilizers, providing additional training stimulus. Stabilizer muscles engaged include Core.
Yes, the Single-Leg Extension is an excellent choice for beginners due to its straightforward movement pattern and lower technical demands. Anyone wanting to isolate each quad. Start with lighter weights to master proper form before progressing.
For the Single-Leg Extension, the recommended approach depends on your goals. 3 sets of 12-15 reps per leg. Rest 45-60s. For strength, use 8-10 reps per leg. For muscle growth, perform 12-15 reps per leg. For endurance, complete 15-20 reps per leg.
The Single-Leg Extension typically requires a machine, which most home gyms don't have. For a home-friendly alternative targeting the same muscles, check the variations section above.
Good alternatives to the Single-Leg Extension include: Leg Extension, Sissy Squat. These exercises target similar muscle groups as the Single-Leg Extension and can be used as substitutes based on your equipment availability, gym setup, or training preferences.
This Exercise Is in Your Plan
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Safety Notes
- Use appropriate weight.
- Avoid jerky movements.