Leg Extension
MachineStrength
The Leg Extension is a machine-based isolation exercise performed seated on a leg extension machine, extending the knees against resistance from a padded lever arm to isolate the quadriceps. Its primary purpose is to build quad strength and size while minimizing involvement from other lower-body muscle groups. It requires a seated leg extension machine, and is well suited to beginners, rehab patients, and lifters seeking targeted quad isolation and definition.
How to Perform Leg Extension
- 1Sit on the leg extension machine with your back against the pad, adjusting the seat so your knees line up with the machine's pivot point.
- 2Hook your ankles behind the lower padded lever, positioning it just above your feet, and grip the side handles for stability.
- 3Set the resistance to an appropriate weight on the machine's stack, keeping your back flat against the backrest.
- 4Inhale to prepare, then exhale as you extend your knees, lifting the padded lever up until your legs are straight, squeezing your quads at the top.
- 5Hold the top position briefly, continuing to flex your quads against the pad.
- 6Inhale as you slowly lower the pad back down to the starting position with control, allowing your knees to bend fully.
- 7Repeat for the prescribed reps, keeping the movement slow and controlled throughout each set.
- 8Key form tips: Keep the movement slow and controlled to maximize quad activation—avoid swinging or using the machine's momentum. Maintain a neutral spine against the backrest and avoid arching your lower back off the pad. Common mistakes: partial range of motion (not extending fully), locking the knees hard at the top, or leaving the seat position mismatched to your knee joint.