Leg Extension
How to do it
Starting position
- Sit with your back and lower back fully pressed against the backrest.
- Adjust the pad so it rests against the front of your shins, just above your ankles.
- Align the axis of rotation of your knees with the machine's axis of rotation.
- Grip the handles firmly and stabilize your upper body.
Movement
- Pull the tops of your feet toward your body so your toes point up.
- Exhale and extend both legs straight up.
- When lowering your legs, resist the weight and slowly return to the starting position.
Breathing
Exhale as you extend your legs and inhale as you lower them.
Trainer tips
- Fully extend your knees and feel the contraction
- Pause for 1 second at the top
- Control it slowly as you lower
Cautions
- If your hips lift midway, it strains your lower back, so keep them planted on the seat.
- Slamming your knees down shocks the joints, so always lower with control.
- Kicking the legs up with momentum
- Lifting the hips off the seat
Exercise info
| Primary muscles |  Quads |
|---|---|
| Equipment |  Leg extension |
| Movement pattern | Isolation |
| Rep range | 10–15 reps |
10 similar exercises
Representative exercise: Leg Extension
- Lever Isometric Leg Extension
- Machine Leg Extension (Plate Loaded)
- Standing Alternating Knee Extension
- Sitting Knee Extension on a Stability Ball
- Machine Leg Extension (Inward Toes)
- Glued Heels Leg Extension on a Chair
- Machine One Leg Extension
- Lever Single Leg Extension (Plate Loaded)
- Machine Alternate Leg Extension (Plate Loaded)
- Seated Alternate Knee Extension on Chair
Exercise GuideAre you kicking your legs up with momentum?Watch the video and see how to fix it
How GYMKC sets the weight for this exercise
For example, if you do 10 reps with 40 kg and log that you could have done about 2 more, GYMKC estimates your 1RM at about 57.6 kg.
With the leg extension, each step is 5 kg (10 lb), so the next weight is 45 kg. Within your 10–15 reps target, the sets you log decide whether to add reps first or add weight.
These numbers are an example of how the calculation works. Your actual prescription is recalculated every set from your own records. See how the calculation works
Related exercises
Machine Leg Extension (Inward Toes)HarderLever Seated Leg ExtensionHarderCable Seated Leg ExtensionSimilar exerciseBodyweight Kneeling Sissy SquatSimilar exerciseGoblet SquatSimilar exerciseDumbbell Seated Leg ExtensionSame muscle · different equipmentLandmine Sissy SquatSame muscle · different equipment
This information is based on our analysis of public content from evidence-based training experts in Korea and abroad. It is not a substitute for medical advice.
Weights and sets differ from person to person. The GYMKC app uses the sets you log to calculate the weight and reps for your next set.