Why should I do leg extensions one leg at a time?

Single-leg training allows you to identify and fix strength discrepancies between your left and right legs. It also improves mind-muscle connection by allowing you to focus entirely on the contraction of one quad at a time.

Is the single leg extension safe for my knees?

When performed with controlled tempo and appropriate weight, it is a safe isolation movement. Ensure your knee is aligned with the machine's axis of rotation to minimize shear force on the joint.

How heavy should I go on this exercise?

This is an isolation exercise intended for hypertrophy and detail rather than max strength. Use a weight that allows for 10 to 15 controlled repetitions with a brief pause at the top.

Single Leg Extension Guide: Form, Benefits, and Tips

Master the single leg extension to isolate your quads and fix muscular imbalances. Step-by-step instructions for better leg definition and knee stability.

How to Perform

Adjust the seat back so your knees align perfectly with the machine's pivot point and your back is firmly supported.
Position the lower leg pad just above your ankles and select a lighter weight than you would use for bilateral sets.
Grip the side handles firmly to stabilize your hips and prevent your glutes from lifting off the seat during the movement.
Extend your right leg fully until it is straight, focusing on a hard contraction of the quadriceps at the top.
Pause for one second at peak extension before slowly lowering the weight back to the starting position under full control.
Complete all repetitions for the right leg then switch to the left leg to ensure equal work distribution.

Common Mistakes

Using momentum or swinging the weight instead of using muscle contraction.
Allowing the hips to rise off the seat during the extension phase.
Setting the ankle pad too high on the shins or too low on the bridge of the foot.
Locking the knee joint aggressively rather than focusing on muscle tension.

Muscles Worked

Primary movers

Quads

Stabilizers

Rectus femoris
Vastus lateralis
Tibialis anterior

Related Guides

Quads · Legs