Written by Paulina Kairys | BSKin & EX.Sc., NASM CPT
Fact checked by Kirsten Yovino, CPT Brookbush Institute
FACT CHECKED
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Leg extensions are a go-to exercise when it comes to directly targeting the quadriceps. It’s a killer way to finish a leg day. But, you may be wondering what your options are if your gym doesn’t have a leg extension machine (or it's often taken) or you’re working out from home with limited equipment? Well, you don’t need to let your leg gains suffer, there are plenty of other great alternatives to leg extensions that will hammer your quads.
The key to substituting the leg extension machine is to use exercise variations that follow the same or similar biomechanics and have adequate loading potential. This way you can achieve the desired stimulus for your quadriceps according to your training program and you can apply exercise progressions over time. This is the approach we've taken when considering the top leg extension machine alternatives.
Table of contents:
- What is the leg extension and what muscles does it work?
- Benefits of quad isolation exercises
- Are leg extensions bad for your knees
- What makes for a good leg extension alternative?
- 5 best leg extension alternatives
- Quad training programming tips
- Why you may not want to replace the leg extension machine
WHAT IS A LEG EXTENSION MACHINE & MUSCLES WORKED
Leg extensions performed on a leg extension machine start in a seated position where the back is resting against the seat and the hips and knees are in a flexed position. Both legs press against a weighted pad, positioned at the lower shin, into an extended position of the knees. The quadriceps repeatedly initiate knee flexion and extension. This action directly isolates the quadriceps muscles, located at the front part of the upper leg.
The quadriceps femoris muscle group consists of four individual muscles in the anterior compartment of the thigh; rectus femoris, vastus medialis, vastus lateralis and vastus intermedius. They originate at the ilium (upper hip bone) and femur (thigh bone) and come together and attach at the patella (kneecap) via the quadriceps tendon. The patella inserts in the tibia (shin bone) via the patella tendon. Out of all the quadriceps muscles, only rectus femoris crosses both at the hip joint and knee joint. The remaining three muscles just cross at the knee joint. Although these muscles have different origins, they share the same tendon that inserts in the patella. The quadriceps femoris extends the leg at the knee joint and flexes the thigh at the hip joint.
Here's a quick breakdown of the quadriceps muscles:
- Vastus Lateralis: The largest of the four quadriceps muscles. The vastus lateralis runs along the outside of the thigh, connecting the femur (thigh bone) to the patella (knee cap).
- Vastus Medialis: This muscle is easily identified as the “teardrop” muscle. It runs along the inside of the thigh connecting the femur to the patella.
- Vastus Intermedius: The vastus intermedius is deepest of the four muscles, it runs in between the two vastus muscles; vastus lateralis and vastus medialis, hence the name intermedius.
- Rectus Femoris: The only quadriceps muscle that crosses both at the hip joint and the knee joint. It runs straight down the leg and flexes the thigh at the hip joint and extends at the knee joint.
Leg extension takes place in the sagittal plane/medial plane. Primary movement takes place through the knee joint; a hinge joint. Hinge joints allow flexion and extension in one plane with limited degrees of motion in all other planes, we can compare the similarities of the knee joint to a hinge on a door.
The knee joint joins the femur (thigh bone) and tibia (shin bone) together, while the fibula (calf bone) and patella (knee cap) are smaller bones that make up the knee. Tendons connect the bones of the knee to surrounding leg muscles that move the knee joint. Ligaments join the knee bones and absorb shock and provide stability in the knee.
In the upward phase of leg extension, or the concentric contraction of the movement, rectus femoris, vastus medialis, vastus lateralis and vastus intermedius are engaged. During the downward phase, rectus femoris, vastus medialis, vastus lateralis and vastus intermedius cause flexion which eccentrically loads the muscle group.
BENEFITS OF ISOLATING OR EMPHASIZING YOUR QUADRICEPS WITH QUAD-DOMINANT EXERCISES
Compound leg exercises such as squats, deadlifts and lunges all activate the quadriceps but do not isolate them. Exercises that solely isolate the quads, like leg extensions, load them directly and build strength. Not only do quad isolation exercises strengthen the quad muscles, the surrounding anatomy of the patellar tendon and quadriceps tendon build resilience to resistance.
Are leg extensions bad for your knees?
It is a common misunderstanding that leg extensions are bad for the knees when in fact, strong quadriceps lead to an increased stability of the knee joints. As long as quad isolation exercises follow consistent progressive overload with proper form, the final result of increased quad strength will follow.
But wait, there’s more to them then building strong knees...
Here are a few more benefits of quad-isolation exercises:
- Overall, stationary machines are great for isolating muscle groups as well as simplifying the movement, especially for beginners. In instances where a machine is not available (the leg extension machine), there are a variety of exercises that solely isolate the quads with a decreased complexity in movement (you’ll see a list of alternative leg extension exercises below).
- Isolating the quads at the end of your leg day is an exceptional finisher to a well-rounded workout. An example of how this can be applied is starting a leg session with a compound movement like a barbell back squat and finishing off with an accessory movement, the banded leg extension. This will hit the quads with more intensity and can leave the quadriceps feeling especially fatigued. It is a common sensation to physically feel the quadriceps tense up especially after isolating them.
- While doing compound exercises, the body expends a large amount of energy. Let’s use the barbell back squat for instance: it is categorized as a lower push exercise, a quad dominant movement that also targets a series of muscles like the quads, hamstrings, glutes, abdomen, lower and upper back. That takes a lot of energy to muster up quality reps. As for isolation exercises, it requires less of a full-body effort and more focus on one muscle group.
- You may have experienced performing a compound movement and not being able to feel a specific muscle working. This phenomenon occurs when there is a lack of neuromuscular connection within a muscle and movement associated with firing that muscle. Isolating muscle groups, in this case the quads, can help bring awareness to the “squeeze” throughout the range of motion. You’ll be able to feel the isolated muscle working within the range of motion without having to worry about all the surrounding muscles working in a compound lift. In time, this builds neuromuscular connection and can be translated into different movement patterns, with varying complexities.
Don't forget your hamstrings - It is worth noting that most people are quad-dominant and an equal amount of training effort should be applied to training the posterior chain; back of the legs (hamstrings and glutes). A well-rounded program can help achieve well-rounded strength gains in all areas of the lower body.
WHAT MAKES FOR A GOOD LEG EXTENSION ALTERNATIVE?
If you do not have access to a leg extension machine or you simply want exercise variety, you can still replicate the leg extension in several different ways. Some alternatives are better suited than others according to your training goals, your physical capabilities and the progressions applied to the movement.
The three questions below are a great guide to help narrow down your most optimal leg extension alternative:
Does the exercise target the quads as best as possible?
If there are specific movement patterns that you struggle with, like lunges for instance, then look to simplify the movement. Instead of doing a full reverse lunge and feeling like you are losing balance, choose a split squat or an assisted split squat instead (meaning you can use one hand to hold onto something).
With movement patterns that we struggle with, there may not be a strong neuromuscular connection to the muscles involved. Most likely, the body is still trying to figure out the movement pattern itself and build practice through repetitions. In this case, choose movements that help you physically feel the isolation of just your quads. If you know that heel-elevated squats help you feel your quads the most, choose the squats and leave the lunges as practice for a standard leg day.
Does the exercise follow the same biomechanics?
The biomechanics of leg extensions are quite simple, the legs press the resistance away and come into a fully extended position at the top. Leg extensions are done in the sagittal plane and alternative movements should follow the same guideline.
A heel-elevated squat with a narrow stance is an appropriate alternative, the prime moving joints are the hips and knees while the legs move in the sagittal plane.
Now let’s take the sumo squat, you may feel activation in the quads but this position sets the hips in external rotation which switches the plane of motion from sagittal to transverse. The sumo squat incorporates a lot of adductor and glute activation and may not be the most optimal exercise to isolate the quads.
Can you progress this movement?
Progressions take time and can look very different for each exercise. Most progressions require equipment while others require using your own body to increase the difficulty of the movement.
Here is a list of progressions that can be incorporated for most leg extension alternatives:
- Increase in sets and repetitions.
- Utilize heavier resistance.
- Load one leg at a time.
- Change the resistance mechanism (ex: machine to bands).
- Hold in an isometric position (at any point of the ROM).
- Eccentric loading (slow on the way down).
- Concentric contraction (fast on the way up).
Based on the above, here are the best alternatives that you can do at the gym or at home if you have no leg extension machine or you want a variety/better options, and then several for if you are working out at home without any conventional equipment.
If you feel like a leg extension machine is irreplaceable (understandably so), check out our recommended list of the top leg extension machines for home gyms. It covers budget, premium, space-friendly, and multifunctional options. We will show you our top pick for a home gym leg extension machine at the end of this post.
LEG EXTENSION MACHINE ALTERNATIVE LIST
Free Weights:
- Reverse Lunges
- Step Ups
- Lateral Step Ups
- Front Foot Elevated Split Squat
- Bulgarian Split Squat
- Elevated Heel Goblet Squat (Narrow Stance)
- Narrow Stance Leg Press
For more great leg press options, check out our article on the 7 Leg Press Foot Placements!
Banded/Cable:
- Seated Leg Extension
- Standing Single Leg Extension
- Banded Squats
- Cable Front Squats
Bodyweight:
- Elevated Heel Squat (Narrow Stance)
- Step Ups
- Split Squat
- Bulgarian Split Squat
- Sissy Squat
- Lateral Step Ups
5 BEST LEG EXTENSION ALTERNATIVES
From the above list, let's breakdown our 5 favorites...
1. BULGARIAN SPLIT SQUAT
Difficulty Level: High
Ideal Reps: 10+ Reps Each Leg
Instructions:
- Take two steps away from a bench and face your back to the bench.
- Place one foot on top of the bench. Make sure the top of your foot lies flat on the bench.
- Square your hips forward and position your legs about shoulder width apart.
- Bend through both knees and descend to the bottom position of your split squat. The thigh of your front leg should be parallel to the floor. Your back thigh should stay relatively vertical in the bottom position.
- Press your front foot through the ground while placing tension in the back leg to return to the start position.
Pro Tips: It may take some adjusting to find your starting position in the Bulgarian split squat. One hack is to position yourself in a secure bottom position (front thigh parallel to the ground, back thigh vertical and back foot pressing into the bench/step). From here, you’ll find stability in your form and will be able to press out of the bottom position and come up to standing without losing balance. Use anything that is stable in your surroundings to help you with balance if needed.
Progression: Eccentric Bulgarian Split Squat (slow down the negative movement)
2. ELEVATED HEEL SQUAT (NARROW STANCE)
Difficulty Level: Moderate
Ideal Reps: 8-15 Reps
Instructions:
- Elevate your heels by using standard weighted plates or a short step that lifts your heels about 2+ inches off the ground. This should feel comfortable on your feet. If you feel discomfort through your feet at any point, find a shorter step.
- Position your feet about shoulder width distance apart and point your toes straight forward. Note: A narrow stance is preferred for this variation.
- Keeping your back vertical, bend through your knees and send them past the toes at the bottom position of your squat. Make sure your knees track your toes.
- Drive through the feet and come back up to standing.
Pro Tips: A narrow stance in the elevated heel squat helps maintain a more upright posture and direct focus on loading the quads. Elevating the heels may also increase the range of motion in your squat. Make sure to maintain tension through the movement, especially at the bottom of the squat. For a challenging progression, add a weight in the goblet position (at the chest).
Progression: Elevated Heel Squat with Pause (pause at the bottom of the rep)
3. STEP UPS
Difficulty Level: Moderate
Ideal Reps: 10-12 Reps Each Leg
Instructions:
- Start by standing about a foot away from a bench/step. Secure one foot on top of the bench and the other foot planted on the ground.
- Slightly hinge from the hips and lean your torso towards the front foot.
- Displace your weight into the front foot, push through the bench and come up to a standing position at the top.
- Keep the same foot planted on the bench and slowly bend through the knees and lower your opposite foot to the ground.
Pro Tips: Step ups in strength training are most efficient when negating any bouncing or momentum. It is common to see a bounce initiated when trying to step onto the bench. Instead, think about leaning and displacing your weight through the bench to help you stand in a vertical position. This activates the quads along with the glutes. A slow descent downwards will test your strength and balance. If you are training your right leg, make sure it stays on the bench the entire time so you benefit from the step up (concentric contraction) and step down (eccentric loading).
Progression: Eccentric Step Up
4. SEATED BANDED LEG EXTENSIONS R/L
Difficulty Level: Low
Ideal Reps: 12-15 Reps Each Leg
Instructions:
- Sit down on a bench or chair that positions your hips in a 90 degree angle. Having back support in this position is a plus but not required.
- Secure the band behind you and attach it around one shin or your ankle (for more resistance, just fold the band up and loop it through your lower leg, the more tension on the band from the bottom position, the more resistance you will have - ideally you want the band to be quite taut from the starting position).
- Start in a hip and knee flexed position and resist the band as you push into leg extension. Stay seated in an upright position throughout the exercise.
- Repeat on each leg.
Pro Tips: Focusing on one leg at a time for the banded leg extension can ensure that you keep balance on the bench and are able complete repetitions with proper form. If you’re ready to try looping both shins through the band to train both quads simultaneously, be prepared to engage your core to stay stable on the bench.
Progression: Standing Banded Leg Extensions
If you don't have resistance bands, check out our recommendations for the best workout bands.
5. REVERSE LUNGE
Difficulty Level: Moderate
Ideal Reps: 10-12 Reps Each Leg
Instructions:
- Start in a standing position with your feet about shoulder width apart.
- Send one foot straight back while remaining in your shoulder width stance.
- Keep tension through the front foot and on the descent bend through both knees, creating 90 degree angles through the knees.
- Return to standing by shifting most of your weight through the front foot.
Pro Tips: Leaning the torso slightly forwards over the working leg, helps shift most of the weight into the front foot. This helps isolate the quads and helps the body find balance. Use anything that is stable in your surroundings to help you with balance if needed.
Progression: Front Foot Elevated Reverse Lunge
Related:
PROGRAMMING TIPS FOR QUAD EXERCISES
Set specific goals for your program. With quad isolation exercises, it is recommended to perform them after any compound lifts like barbell back squats. This way you can confidently fatigue the quads knowing most of your effort has been spent in the compound lift. An exercise like a seated cable leg extension requires significantly less neuromuscular control and full-body effort compared to a barbell back squat.
When it comes to sets and repetitions, quad isolation exercises fall in the category of 8-15 repetitions. This is dependent on the weight, stimulus goal and accessibility to equipment. If you are performing this at home with limited equipment, higher repetitions are a reasonable goal as long as you are able to maintain form and technique throughout those higher repetition ranges. If you have access to a gym with a broad selection of tools, play around with a variety of weights that complete the given stimulus with less repetitions. Example: Banded leg extensions fatigued at 18 reps vs. Cable leg extensions with moderate weight fatigued at 12 reps.
Choose quad isolation exercise alternatives that help you feel the most quad activation. Hone in on properly executing the form along with feeling the muscles activate through the given range of motion. Focus on physically squeezing your quadriceps through the movement. This will help build neuromuscular connection.
Don’t be shy to throw in progressions and a variety of exercise alternatives, but not all at once. It takes a fair amount of repetition to build proper patterning in the body while reaping the benefits of building strength. Slowly introduce a few variations or progressions of quad extension exercises to your training block and allow your body to adapt over time.
Example: My training block is 6 weeks. Throughout the 6 weeks I have banded leg extensions programmed. Week 3 and 4 I’ll supplement an eccentric banded leg extension and Weeks 5 and 6 I’ll incorporate high rep eccentric banded leg extensions. For the entire training block, leg extensions will be followed as prescribed. Weeks 4-6 introduces a progression to challenge the leg extension.
FINAL THOUGHTS ON LEG EXTENSION MACHINE ALTERNATIVES
Leg extensions and the variations of leg extension exercises isolate the quadriceps muscles. The key to replicating leg extensions is choosing exercise variations that follow the same biomechanics, completing a desired stimulus according to your program goals and applying exercises that suit your abilities. Introducing a variety of leg extension alternatives incorporates new stimuli in a program and helps gain overall strength and neuromuscular connection. An important factor to keep in mind is to limit an overwhelming amount of variety or progressions in a training program block. Allow your body to reap the benefits by slowly introducing new quad isolation variations.
Don't want to replace the leg extension machine?
There is a reason the leg extension machine is a go to for lifters of all levels. It's a great exercise for truly isolating the quads and building definition. While it's by no means a primary leg builder, the leg extension machine is a great finisher to any leg day. It allows your quads to get great eccentric, concentric and isometric contraction (stretching, squeezing contraction, and holding contraction). Its specific usage is hard to replace.
So, if you don't want to replace the leg extension machine for at-home workouts, there's good news! You can easily find one that fits your budget and space. Here's our recommended list of the best leg extension machines for home gyms, which covers affordable, premium, small space, and multifunctional options.
And if you don't want to read through that, our top pick from the list is the Body-Solid Leg Extension and Curl Machine. It is a super solid machine for serious fitness enthusiasts, which, as the name suggests, doubles as both a leg extension and leg curl machine.
Constructed of 7-gauge steel, this commercial grade leg extension and curl machine is designed to withstand a heavy workout...
Here are more alternative exercises for machines you may not have access to:
Paulina Kairys
Author