How Many Sets And Reps For Leg Extensions To Optimize Your Workouts And Train Safely
By: Zack Mathews, NASM - CPT, CES, & PES, PN-L1

Learning how many sets and reps for leg extensions will help you decide how to balance your leg workout between heavy compound movements like squats, and smaller accessory movements, like leg extensions.
The ideal sets and reps for leg extensions will depend on your experience level, what your current goals are, and what else you will be doing in your workout.
For the average gym goer, 2 - 5 sets of anywhere between 6 - 25 reps of leg extensions will help you build strength and muscle. Rest 2 - 3 minutes if you do between 6 - 12 reps as this is considered more hypertrophy (muscle building) or 1 - 2 minutes if you do 12- 25 reps as this is more muscular endurance.
I’ll tell you this. You can get a really great pump in your legs if you pick the right weight while doing these!
Let’s break down what type of leg extensions rep scheme is best for you.
Leg extensions are a great exercise for all skill levels, whether you are a beginner or an advanced trainee. Since you’re fixed on a machine, it’s harder to mess things up than say, a barbell squat.
As a beginner, the most important thing you can do is take the time to learn perfect form before you start aggressively increasing weight. You want to have control with the weight at the top and on the way down, without banging the weight on each rep.
If you don’t take the time to learn proper form, you risk having bad form that can lead to knee issues.
Guidelines for leg extensions sets and reps for beginners:
- Perform 2 - 3 sets of 10 - 15 reps.
- Rest 90 seconds - 2 minutes to ensure you are fully recovered after each round.
- Starting in the middle rep range (10 - 15) will allow you to safely train your legs and learn appropriate weights for your body.
- When choosing a weight, find a weight that you do for 10 -15 reps and still have 2 - 3 reps left in the tank. For example, if you do a leg extensions set with 60 pounds for 10 reps, you should be able to do 12 -13 with confidence, but not any more than that. This is a safe spot to train as a beginner.

Once you get comfortable with choosing appropriate weights for leg extensions (and the burn that comes along with it!), you can start experimenting with a wider range of reps that can focus more on hypertrophy or muscular endurance.
Also, you can experiment with pauses at the top, longer eccentrics (lowering the weight), and/or doing one leg at a time.
Additionally, you’ll feel more comfortable pushing the intensity with the movement, allowing you to get closer to failure with your reps.
Guidelines for leg extensions sets and reps for intermediate and advanced lifters
- Perform 3 - 5 sets of 6 - 25 reps.
- Experiment with both lower and higher rep ranges.
- Rest 2 - 3 minutes for a rep range of 6 - 12 and 1 - 2 minutes for a rep range of 12 - 25.
- Use different training techniques (pauses, half reps, single leg, eccentrics) to increase the difficulty.
- Leave 0 - 2 reps in reserve (RIR) on each set. This means you should be getting close to failure on every set.

Frequently Asked Questions
If you can control the weight and it feels fine on your joints, it is ok to go heavy on leg extensions, as long as you are doing at least 6 reps.
Performing reps in the maximum strength range of 1 - 5 reps should be done on your main compound lifts like squat and deadlift variations, not leg extensions.
When picking a weight for leg extensions, you want to choose how many reps you are going to do, and then find a weight that will leave 0 - 3 reps in reserve.
This means that if you want to do 10 reps, you pick a weight that you can do for 10 - 13 reps. If you do a set for 10 reps and get done and think “I could have done 18”, that means you would have 8 reps in reserve. You’ll need to increase the weight.
Finding the appropriate weight for leg extensions takes time so experiment with different weights, track your workouts, and think about how many reps in reserve you have after each set.
You can build muscle in your legs with only leg extensions but you’ll also want to add in compound exercises into your routine, such as squat, deadlift, and lunge variations.
To optimize training, have a mix of compound movements (squats, deadlifts, lunges, etc.) and isolation movements (leg extensions, leg curls, etc).
Recap
As you’ve learned, there is a wide range of options when picking your sets and reps for leg extensions. If you’re a beginner, stick with 10 - 15 reps for less sets and focus on form. Once you get more advanced, add more sets, more variety with rep ranges, higher intensity, and harder variations.