Why it matters

The Leg Extension builds strength and size in your quadriceps. As an isolation movement, it targets those muscles directly to build size and balance.

How to do it

Adjust the seat and any pads so the working joint lines up with the machine’s pivot, set the pin to your working weight, and keep contact with the support pad throughout.
Set the pad against the front of your lower shins and line your knees up with the pivot.
Start with your knees bent and the resistance under control.
Straighten your knees to lift the resistance until your legs are nearly straight.
Squeeze your quads hard at the top for a beat.
Lower under control until your knees are bent back to the start.
Complete all your reps on one side, then repeat with the other, matching the reps on your weaker side.

Straighten your knees fully and squeeze your quads at the top.
Move only at the knees — keep your hips and back against the seat.
Lower under control rather than letting the weight drop.
Drive through your knees and feel the front of your thighs work.
Follow the machine’s guided lever path smoothly and control the weight back to the stack.

Swinging or using momentum to fling the weight up.

A swung weight is lifted by momentum, not your quads.

Instead Move at a controlled speed and let your quads do the work.
Cutting the top short of a full knee extension.

Stopping short of lockout leaves the peak quad contraction untrained.

Instead Straighten your knees fully and hold the squeeze for a beat.
Letting the weight slam down at the bottom.

Dropping the weight skips the lowering phase, where a lot of the muscle work happens.

Instead Lower under control until your knees are bent back to the start.

Tempo: Extend with control and lower for about two counts.
Breathing: Exhale as you straighten your knees, breathe in as you lower.
Range of motion: Move from bent knees to a full, straight-knee squeeze. Take the quadriceps through its full working range each rep.
Setting up: Adjust the seat and any pads so the working joint lines up with the machine’s pivot, set the pin to your working weight, and keep contact with the support pad throughout.
If you are new to it: Use a light weight you can control through the full range.
Once it is easy: Add a pause at full extension for a stronger quad contraction.