How to do a Leg Extension
Reviewed by Jim Parker, CPT, B.A. Kinesiology
Leg Extension Machine
Workouts with Leg Extension
Target muscles worked
Instructions for Proper Form
Leg Extensions are an isolation exercise that target the quads. Due to a severe lack of isolation movements for the lower body, this is a great option for specifically targeting your quadriceps. The use of a machine restricts your range of motion, and adds some stability to the movement. This can help your focus more on exertion than stabilizing the movement. The downside to this exercise is that it places a lot of tension on your knee. Keep your weights light, and focus on pausing near the end of your range of motion.
- Sit upright in a leg extension machine while placing the lower back just above your ankles in front of your lower legs.
- Your knees should be flexed to 90 degrees and the back pad should be contact with your lower back and shoulders.
- Grab ahold of the handles for additional support.
- Extend your legs in an upward arc until your lower legs are aligned with your thighs.
- Return to the starting position.
Common Form Mistakes
Too Much Weight
This exercise inherently places a lot of tension on your knee. Adding too much further increases your risk of injury. You can do this exercise safely by focusing on controlling the movement, and limiting your range of motion prior to fully extending your leg.
Weight & 1 Rep Max Calculator
Average Leg Extension standards by male, female, weight, age and height
Use this calculator to see Fitbod's possible first recommendations for you. This would be your starting line, based on more than 4.5 billion logged sets from 1.1 million users.
- beginner8reps50lbs1 Rep Max65lbs
- intermediate8reps60lbs75lbs
- advanced8reps75lbs95lbs
Enter your stats to calculate your Reps & Weight
Alternatives & Variations to Leg Extension
1. Single Leg Leg Extension
60.6 mSCORESWAPPED 12,090 TIMESSingle Leg Leg Extensions is a variation of Leg Extensions that uses one leg at a time. Like other leg extensions, this isolation exercise targets your quadriceps. By targeting one leg at a time, you can focus your attention on getting good muscle activation in each leg. In addition, this can help you identify and address strength imbalances between legs. While leg extensions can be a great way to build strength and muscle mass in your quadriceps, they can also place a lot of tension on your knees.
2. Leg Press
99.7 mSCORESWAPPED 7,761 TIMESLeg Press is a compound exercise that primarily targets the quadriceps. The exercise itself is fairly similar to a standard squat, with some key differences. The biggest of these differences is the added stability from supporting your back on the Leg Press Machine. The end result of these changes is a more stable movement that further emphasizes your quadriceps. Leg Press is an excellent exercise for anyone looking to build muscle mass or strength in their quads.
3. Machine Leg Press
95.1 mSCORESWAPPED 5,402 TIMESMachine Leg Press is a variation on the more standard Leg Press. Like the Leg Press, this is a compound exercise that primarily recruits the quadriceps. This is a great exercise for building strength and muscle mass in your quads. The use of a machine doesn’t change anything significant about this exercise, although your positioning may change depending on the machine you’re using.
4. Dumbbell Lunge
97.6 mSCORESWAPPED 5,290 TIMESDumbbell Lunge is a variation on the more standard Lunge. Similar to other Lunge variations, Dumbbell Lunge is a compound exercise that primarily targets the quads. The exercise itself is the same as a standard lunge except for the added weight from holding dumbbells in each hand. This is a great variation for anyone looking to make their lunges a bit more challenging without adding more complexity to the movement.
5. Dumbbell Squat
94.1 mSCORESWAPPED 4,772 TIMESDumbbell Squat is a variation of the more standard Squat. Like other variations, this is a compound exercise that primarily targets the quadriceps. The advantage of using dumbbells rather than a barbell is that you have more freedom in your range of motion which can make this a more accessible variation for anyone with mobility limitations. With that freedom comes a bit more instability with this exercise though, which can help you further improve your squat for, and build the strength needed for heavier, or more complex variations.
6. Air Squats
92.1 mSCORESWAPPED 2,880 TIMESAir Squats are a bodyweight variation of Squats. Like other variations, this is a compound exercise that primarily targets the quadriceps. Without any added resistance this is easily one of the most beginner friendly exercises out there. It’s a great way to start building strength, and working your way towards more advanced variations.
7. Back Squat
99.3 mSCORESWAPPED 2,648 TIMESBack Squat is one of the three Powerlifting movements, and one of the most common lower body exercises. It’s a great compound exercise that can help build strength and muscle mass in your leg, especially your quadriceps. It’s a staple in most fitness programs, and is often used as a metric for tracking lower body strength in general.
8. Hack Squat
90.1 mSCORESWAPPED 2,085 TIMESHack Squat is a variation of squats that utilizes a specific machine to add resistance. Like other squat variations, this exercise primarily targets your quads. The use of a machine can assist you by redistricting your range of motion more than with the use of free weights, as well as adds more stability to the movement.