Leg Extensions
A seated machine exercise that extends the knees against resistance, isolating the quads without much involvement from other muscle groups. It stays straightforward for beginners once the machine is set up correctly.
How to do the leg extensions
- Sit on a leg extension machine with your legs under the pad and your feet pointed forward.
- Adjust the pad so it rests just above your feet, with your knees forming roughly a right angle; this is your starting position.
- Hold the side bars for stability as you extend your legs as far as comfortable, exhaling as you lift.
- Pause for a second once your legs are fully extended.
- Lower the weight back down slowly as you inhale, keeping the movement controlled.
- Repeat for the rest of your set without letting the weight drop quickly.
Original library instructions (4 steps)
- For this exercise you will need to use a leg extension machine. First choose your weight and sit on the machine with your legs under the pad (feet pointed forward) and the hands holding the side bars. This will be your starting position. Tip: You will need to adjust the pad so that it falls on top of your lower leg (just above your feet). Also, make sure that your legs form a 90-degree angle between the lower and upper leg. If the angle is less than 90-degrees then that means the knee is over the toes which in turn creates undue stress at the knee joint. If the machine is designed that way, either look for another machine or just make sure that when you start executing the exercise you stop going down once you hit the 90-degree angle.
- Using your quadriceps, extend your legs to the maximum as you exhale. Ensure that the rest of the body remains stationary on the seat. Pause a second on the contracted position.
- Slowly lower the weight back to the original position as you inhale, ensuring that you do not go past the 90-degree angle limit.
- Repeat for the recommended amount of times.
Common mistakes
- Letting the weight drop quickly on the way down; lower it slowly to keep tension on the quads.
- Using a pad position that sits too high or too low on the shin; adjust it just above the feet.
- Arching the back or lifting off the seat to extend further; keep your torso still throughout.
- Choosing a weight so heavy that only a partial range is possible; use a load you can extend fully.
Sets and reps by goal
| Goal | Sets, reps and rest |
|---|---|
| Strength | 3 sets of 8 to 10 reps, 60 to 90 seconds rest |
| Muscle | 3 to 4 sets of 10 to 15 reps, 60 seconds rest |
| Endurance | 2 to 3 sets of 15 to 20 reps, 45 seconds rest |
Ranges, not prescriptions. Start at the low end and add a set or a rep when every set feels controlled.
Tips
- Keep the machine settings the same each session so you can track your progress accurately over time.
- Use a lighter weight and a slower tempo if your knees feel any discomfort during the lift.
In the app: this exercise is one of 873 in GymPilot's library, with the same photos, form cues and a link back to the moment in an imported video it came from.
Questions
Is the leg extension machine good for beginners?
Yes, the seated, guided motion makes it one of the easier machines to learn correct form on.
What muscles does the leg extension work?
It is focused entirely on the quads, extending the knee against resistance.
