I added the leg extension machine to my leg day routine — here’s why it was a great addition

a photo of a woman working out her quads on a leg extension machine inside a gym
(Image credit: Getty Images)

I have always favored lower body over upper body sessions at the gym. I’m a runner, so I get more out of strengthening my lower body than my upper body and I can't help but find myself getting bored during an upper body day at the gym. Always on the hunt to add to my favorite lower body days, I started making use of the leg extension machine at my local gym and I am loving what it adds to my sessions.

The leg extension machine is designed to isolate and strengthen the muscles of the quadriceps, which are the large muscles at the front of the thigh. The machine typically consists of a seat with a backrest, a lever, and a padded bar that rests just above the ankles. You sit on the seat, place your lower legs under the padded bar, and lift the legs by extending the knees against resistance. As you lift the legs and extend the knees, the quadriceps contract to perform the movement. 

I combined sets on the leg extension machine with compound movements like squats and lunges to ensure my workouts were contributing to balanced muscle development and overall lower body strength. Here’s how I got on…

 How to you use a leg extension machine 

an illustrated photo of a man using the leg extension machine

(Image credit: Shutterstock)

If you suffer from a knee condition or your knee is injured, please seek advice from a professional before incorporating leg extensions into your workout routine. If this does not apply to you and you are injury free, follow the instructions below.

  • Adjust the seat height so that your knees align with the pivot point of the machine.
  • Set the weight level. Beginners should start with a lighter weight and gradually increase as they become more accustomed to the exercise. You can read more here about progressive overload and its benefits.
  • Sit on the machine with your back against the backrest and your feet flat on the floor. 
  • Place the back of your lower legs under the padded bar, just above the ankles. Hold onto the handles or the sides of the seat for stability and balance. 
  • Slowly extend your legs straight in front of you by lifting the padded bar. Fully straighten your knees without locking them.  
  • Exhale as you extend your legs and focus on contracting your quadriceps throughout the movement. Hold the extended position for a brief moment to maximize muscle engagement. 
  • Slowly lower the padded bar back down towards your shins, bending your knees. Inhale during this phase, and avoid letting the weights slam down.
  • Repeat the leg extension for the desired number of repetitions, typically 8-12 for muscle hypertrophy and 12-15 for muscular endurance. 

I added the leg extension machine to my leg day routine — here’s why it was a great addition

Instead of spending all of my time in the squat rack or by the free weights, I decided to start using the leg extension machine in my lower body gym sessions. Here’s what happened…

I loved being able to isolate my quads

The leg extension machine is designed to specifically target the quads so you are guaranteed a proper quad burn when you hop onto one of these machines. 

I am in the midst of marathon training and need to make sure I have strong quads to propel my body forward every step of the way. The quads also provide stability to the knee joints, an area of the body that is put under a lot of stress while running long distances. Using the leg extension machine to strengthen my quads is one way to help support my knees and reduce the risk of injury in the lead up to my race. 

I liked that it didn’t put stress on my back

Unlike some compound exercises, such as squats or deadlifts, the leg extension machine puts minimal stress on the lower back. While I don’t personally suffer from any long term back pain issues, I do like that my back isn’t put under any strain during this exercise. 

Especially on days where my body feels a bit fatigued in the gym, sometimes I need less compound movements where multiple muscles are involved and I need more isolation exercises like leg extensions to just focus on one muscle at a time. 

a photo of a woman working her quads on the leg extension machine in the gym

(Image credit: Getty Images)

The machine is easy to use

If you are new to the gym or perhaps you tend to avoid using any machines when you workout at the gym, it can be daunting knowing how to work a machine that you have never used before. I have previously discussed on Tom’s Guide things I wish I had known before joining a gym, and asking for help with navigating your way around the gym is one of them. Once you familiarize yourself with the gym, the leg extension machine is an excellent piece of equipment for beginners to get started on. 

The machine is pretty user-friendly and requires minimal setup. Although I'm not new to the gym, it’s always nice having something you can jump onto and get set up on in a minimal amount of time. As much as I love working with a barbell, it can make my gym sessions longer than I want them to be with the additional time spent adding and removing weight plates.

I added the leg extension machine to my leg day routine — verdict 

I am a big fan of the leg extension machine and after adding it to my lower body sessions consistently, I think it’s a very valuable piece of gym equipment. It provides a targeted and isolated workout for the quadriceps, helping to strengthen and define these muscles.

The leg extension machine also offers a controlled and guided movement, reducing the risk of improper form and minimizing the engagement of other muscle groups. This makes it a suitable option for people, especially beginners, who want to concentrate on developing specific leg muscles without incorporating complex compound movements.

Lastly, the leg extension machine allows for adjustable resistance, accommodating varying fitness levels. This versatility makes it accessible to both novices and seasoned gym-goers, enabling them to tailor their workouts according to their strength and conditioning goals.

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Jessica Downey
Fitness Writer

Jessica is an experienced fitness writer with a passion for running. Her love for keeping fit and fueling her body with healthy and enjoyable food quite naturally led her to write about all things fitness and health-related. If she isn’t out testing the latest fitness products such as the latest running shoe or yoga mat for reviewing then she can be found writing news and features on the best ways to build strength, active aging, female health, and anything in between. Before then she had a small stint writing in local news, has also written for Runners World UK (print and digital), and gained experience with global content marketing agency, Cedar Communications.


Born and raised in Scotland, Jessica is a massive fan of exercising and keeping active outdoors. When at home she can be found running by the sea, swimming in it, or up a mountain. This continued as she studied and trained to become a PPA-accredited magazine journalist in Wales. And since working and living in London, she splits her time between weight training in the gym, trying new fitness classes, and finding scenic running routes. Jessica enjoys documenting this on her fitness-inspired Instagram page @jessrunshere where she loves engaging with like-minded fitness junkies.


She is a big fan of healthy cooking and loves learning more about this area with expert nutritionists she has met over the years. Jessica is a big advocate for building healthy relationships with food rather than building restrictive attitudes towards it. When she isn’t eating or running she also enjoys practicing yoga in her free time as it helps her to unwind and benefits her performance in other sports.