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8 Best Leg Isolation Exercises (Target Each Muscle Group)

Christiana Mikesch
Published by Christiana Mikesch | Senior Coach
Last updated: August 12, 2023

You must incorporate isolation exercises to have the best possible muscle-building effects for a single or small muscle group.

Based on our observations, specific leg isolation exercises are better for inducing hypertrophy for particular muscle groups than others.

We tested more than 30 isolation exercises and singled out those we believe are the best according to the muscle-building criteria.

Keep reading below to learn everything you need about leg isolation exercises, tips to incorporate them into your weekly split, and more.

Quick Summary

  • The best leg isolation exercises include leg machine extensions, seated hamstring curls, lying hamstring curls, calf raises, single leg extensions, and nordic hamstring curls.
  • You must incorporate both compound or multi-joint and isolation or single-joint exercises to get as strong as possible and build more muscle.
  • Isolation exercises are widely used for injury recovery and demonstrate a core part of every effective rehabilitation program.

Isolation Exercises for Legs

A woman doing isolation exercises for her legs

My team and I tested all leg isolation exercises from the list to ensure the best muscle-building effects and safety.

All exercises are beginner friendly, but some exercises, such as nordic hamstring curls (body weight posterior chain exercise), require significant leg posterior chain strength.

These exercises are the best for isolating muscles such as the glutes, hamstrings, quads, and calves.

Also Read: Leg Exercises for Bad Knees

1. Leg Extension Machine

The leg extension machine is the best for isolating your quads.

The leg extension machine biomechanically sets the body and leg in a proper position for the maximal force generated in the quadriceps muscles.

The weight is placed at the end of our legs, close to our feet, meaning the leverage becomes more significant, and our quads work more to complete the movement.

The entire exercise is knee flexion, where muscles activated include rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius.

How to Perform Leg Machine Extensions:

  1. Set the appropriate weight for a given exercise to complete at least 12 repetitions.
  2. Sit on the leg extension machine and set the attachment, so your ankles come behind the place of their insertion.
  3. Hold the bars beside the leg extension machine with your hands to be more balanced during the exercise.
  4. Start the exercise by extending your knee joint while keeping your ankles in normal dorsiflexion and your hip’s angle constant.
  5. When you reach the fully extended position in your knees, hold for 1 second.
  6. Reverse the motion by flexing at your knee joint to return to the starting position where your knees are bent at about 90 degrees.
  7. Repeat for 12 reps and up to 4 sets.

2. Seated Hamstring Curl

A woman doing seated hamstring curls

Seated hamstring curls begin in the same position as the previous exercise.

The main muscles you work during this exercise are of the posterior chain, meaning your hamstrings.

Hamstring muscles include the semitendinosus, the biceps femoris, and the semimembranosus.

Seated hamstring curls are excellent for rehabilitating hamstring injury since you won’t be allowed to be in an athletic stance in the beginning phases of the recovery.

How to Perform Seated Hamstring Curls:

  1. Assume a sitting position on a leg extension/flexion machine and set the weight appropriately to perform 12 repetitions.
  2. Hold the supporting bars with your hands to place your body in a balanced position during the exercise.
  3. Inhale, brace your core, keep your ankles in slight dorsiflexion, and your back flat.
  4. Start the exercise by flexing your knee joint and keeping the ankle and hip joints fixed without changing their angles.
  5. Flex your knees for 90 degrees or more and hold the bottom position for a second.
  6. Reverse the movement of the exercise to return to the starting position. The eccentric phase of the movement should be controlled.
  7. Repeat for up to 12 repetitions and 3-4 sets.

Also Read: Chair Hamstring Stretches while Sitting

3. Lying Hamstring Curl

A lying hamstring curl is a variation of a seated hamstring curl.

The lying hamstring curl is biomechanically different from the previous exercises since gravity will be more efficient and make completing the exercise harder.

It is also widely used in rehabilitation and earlier phases after the recovery process.

However, you should depend on hamstring curls as much if you are healthy since they don’t represent the most functional exercise for the lower body.

How to Perform a Lying Hamstring Curl:

  1. Load the machine with the appropriate weight to perform up to 10 repetitions.
  2. Assume a lying position on the machine’s bench.
  3. Your feet should be tucked beneath the machine attachment, your back flat, your hands holding bars to balance the body, and your eyes looking at the floor.
  4. Start the exercise by curling or flexing at the knee joint to move your feet close to your buttocks.
  5. Hold for one second when your feet reach the end range of motion, about 25 degrees from your posterior chain.
  6. Reverse the motion of exercise to return to the starting position, meaning extend at your knee joint.
  7. Repeat for around ten repetitions and 3-4 sets.

4. Calf Raises

A person doing calf raises

Calf raises will build your calf muscles.

Calf muscles include gastrocnemius and soleus, essentially the same muscle called triceps surae.

Calf muscles are responsible for ankle plantarflexion, which brings your toe further away from the center of your body.

The calf should be performed at the end of the session or in between the sets since they are as demanding as other exercises from the list.

How to Perform Calf Raises:

  1. Pick one kettlebell weighing between 8 and 16 kilograms and hold it in your left hand.
  2. Place a weight plate in front of the wall, so it doesn’t move if you push it forward.
  3. Assume standing with your right leg on the end of the weight plate while holding the dumbbell in your left hand.
  4. Your right hand should be out against the wall to give you support and balance out the body.
  5. Start the exercise by lowering yourself to the floor only in your ankle joint while keeping your knees slightly flexed and back flat.
  6. When you reach maximum dorsiflexion in your ankle joint, reverse the movement by doing plantar flexion to return to the starting position.
  7. Repeat for three sets of up to 15 repetitions.

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5. Single Leg Extensions

Single leg extensions are performed on a leg extension machine and represent a unilateral variation primarily used in the recovery of athletes.

These unilateral leg extensions activate muscles such as rectus femoris, vastus, medialis, vastus lateralis, and vastus intermedius.

Also, you may alternate between the single leg and bilateral leg machine extensions to get the best muscle-building effects.

How to Perform Single Leg Extensions:

  1. Assume a sitting position on a leg extension machine, keep your back flat, and hold the bars near the machine with both arms.
  2. Set the weight so you can perform 6-8 repetitions with a single leg before switching to the other leg.
  3. Start the exercise by pushing the leg attachment and extending your knee joint.
  4. Hold the position for one second when you extend your knee joint fully, and it becomes parallel to the ground.
  5. Slowly and with control, bend your knees to return to the starting position where the angle between your upper and lower leg posteriorly is the same or more than 90 degrees.
  6. Repeat for up to 8 repetitions before working out the other leg.

6. Nordic Hamstring Curl

A woman doing nordic hamstring curls

Nordic hamstring curl is excellent for bulletproofing your posterior chain and lowering the risk of potential injuries.

It is a bodyweight exercise where you control your body's falling with your hamstrings.

In addition, it is excellent for runners and all sports where running is essential.

The best way to progress nordic hamstring curls is to hold weight plates in your hands during the movement.

How to Perform Nordic Hamstring Curls:

  1. Ask a partner to help you and hold your legs during the exercise.
  2. Place a mat on the floor and assume a kneeling position where the angle between your upper and lower leg is about 90 degrees.
  3. Your hands should be in an anatomical position or crossed on your chest muscles.
  4. Ask a partner to stand behind you and hold your legs so you can lower yourself to the ground without tipping off.
  5. Start the exercise by slowly lowering yourself to the floor by extending the knee joint.
  6. When you reach the point where you can't control your body anymore, fall on the ground and absorb the force with your hands, like during a push-up.
  7. From the bottom position and with the help of your hands, bring your upper body back to the starting position where your legs are bent at 90 degrees.
  8. Repeat for up to 6 repetitions and three sets.

7. Hip Adduction (Machine)

Hip adduction on the machine is a solid isolation exercise that will strengthen your adductor muscle complex.

The adductors muscles include the adductor magnus, longus, and brevis.

However, some other muscles that will also be strengthened include the gracilis and obturator externus.

Strengthening your adductors is essential for preventing injuries and stabilizing your body during dynamic bilateral movements.

How to Perform Hip Adduction on a Machine:

  1. Assume a sitting position on the hip adduction machine and set the weight appropriately to perform up to 10 repetitions.
  2. Start the exercise by adducting at your hip joint or bringing your legs toward the middle section of your body.
  3. Hold that position with isometric contraction for one second when your thighs come as close to each other as possible.
  4. Reverse the motion by slowly abducting your legs to return to the starting position.
  5. Repeat for up to 10 repetitions and a maximum of 3 sets.

8. One-Legged Cable Kickback

A woman doing one legged cable kickback in the gym

One-legged cable kickback is one of the best isolation exercises for targeting your gluteus maximus, gluteus minimus, and gluteus medius.

The hamstring muscles, such as semimembranosus, semitendinosus, and biceps femoris, will work too.

This exercise represents an excellent accessory lift you may perform after a similar compound exercise targeting the same muscle groups.

Also, the cable machine will make cable kickbacks functional, meaning they will have the most significant carryover to real-life activities.

How to Perform One-Legged Cable Kickbacks:

  1. Set the weight on the cable machine appropriately to perform up to 8 repetitions with a single leg before switching to the other.
  2. Take a strap and wrap it around your ankle joint.
  3. Face the cable machine while placing your hands on it for added support and to balance out your body.
  4. Start the exercise by extending the single leg at the hip joint while flexing your knees.
  5. When you fully extend your leg, hold that position for one second.
  6. Reverse the entire motion by flexing your hip joint to return to the starting position.
  7. Repeat for up to 8 repetitions and 3-4 sets.

Benefits of Isolation Exercises

A couple doing isolation exercises at home

Every workout routine should contain isolation exercises [1].

Multiple muscle groups experience benefits from compound exercises, but isolation ones are better for increasing the hypertrophy and maximal strength of a specific muscle group [2].

Find some of the most crucial benefits of isolation exercises below.

"Isolation exercises are those used to tackle one specific muscle group or joint ‘in isolation’. While in reality no exercise will only use one muscle group, isolation exercises specifically target one area. Although isolation exercises can be very simple, they are best used once you have built good overall strength, so are typically used in more advanced training routines."

- Phil Goulding, Nuffield Health Senior Personal Trainer

1. Isolation Exercises Help You Fix Muscle Imbalances

Compound squats, single-leg squats, and lunges will build your quads and activate your hamstrings.

This is because hamstrings are attached to the knee and hip, meaning they have two separate functions for each joint.

Squats focus more on the quadriceps than the hamstrings. 

This means that only doing compound exercises such as squats will build your quads, but the hamstrings won't follow the growth simultaneously.

This is crucial since imbalance from anterior and posterior chain muscles often leads to injury or at least a higher chance of getting injured.

That's why you should add isolation exercises.

They help avoid muscle imbalances and can serve as accessory lifts to further increase muscle growth [3].

2. Isolation Exercises Help You to Target Specific Muscles

A woman doing leg isolation exercises at home

Multi-joint or compound exercises target multiple muscle groups, which is excellent for muscle growth or increasing strength.

However, muscle tears and pulls occur when you overwork a particular muscle group with compound exercises.

For instance, it isn't a good idea to work your triceps and shoulders and perform a chest workout routine primarily focused on bench pressing in one day.

Your body still didn't recover from the previous workout routine, meaning you will have other muscle tears and spasms.

In the supercompensation theory, you should allow your body or muscles to recover at least 48h before hitting them again. This time range is highly individual, but most individuals can recover after the 48h have passed. 

That's why you must alternate different muscle groups and create splits based on movement patterns, ensuring you hit different movement patterns every time.

However, what if you trained your triceps and shoulders but want to work your chest? You should incorporate isolation chest exercises, and you will avoid getting overtrained.

3. Isolation Exercises Can Help You Recover From Injuries

Multi-joint or compound exercises are challenging and often lead to injury when pushing your limits or testing one repetition maximum of a particular exercise.

If you have recently experienced injury from doing compound exercises, you may wonder if there are still exercises to perform even though you are injured.

The answer is isolation exercises, meaning you can choose isolation exercises to avoid targeting the injured muscle group or joint.

When injured, you will stay in shape and prevent muscle atrophy by doing isolation exercises.

Some even include c, but only if the trunk isn’t what is injured [4].

Which Isolation Exercises Can I Do?

A woman warming up for isolation exercises

You can do all the isolation exercises.

However, the exercise selection will vary depending on your goal.

Isolation exercises are excellent for local muscle hypertrophy, preventing injuries, and serving as accessory lifts.

You should do between 6-12 repetitions and up to 4 sets to induce the most significant hypertrophy effect using isolation exercises.

The rest between the sets should be at most 90 seconds. This time interval has been proven to be the most effective for the growth of muscle fibers.

Also, you can use isolation exercises to prevent injuries or rehabilitate after the damage has occurred.

To prevent or at least reduce injuries, you should incorporate isolation exercises that will activate weak muscle groups that need strengthening.

Lastly, you may use isolation exercises to support your main or compound exercises.

After you complete the most crucial compound or multi-joint exercises of the day, you can transition to less demanding isolation or single-joint exercises.

This will ensure you get the most from every workout, build muscle, and holistically develop your body.

Isolation Exercises vs Compound Exercises

A gym coach defining isolation against compound exercise

Isolation exercises are almost always single-joint and only target specific muscles or muscle groups.

Compound exercises are always multi-joint and activate large muscle groups, requiring them to work synergistically to complete the movement.

Both types of exercise are helpful and should be incorporated into a single recommended workout program [5].

However, there are specific rules to follow when programming these exercises.

The first rule is always to perform compound first and isolation movements at the end.

This is because compound exercises require more energy and dedication from your central nervous system to complete.

Do not perform them when tired or not concentrated because you may injure yourself.

The second rule is to pair adequate compound exercises with isolation exercises.

This means you should pair two types of exercises according to the same muscle group.

For example, if the first compound exercise you perform is squat, you may supplement it with isolation movements such as hip thrust or leg extension machines.

The principle is that compound exercises are more important for developing most muscles in your body.

Isolation exercises can serve as supplementary lifts or to reduce muscle imbalances.

"Compound exercises should make up the bulk of your lower body workouts. In addition, a compound exercise is more complex, and the risk of technique breakdown is greater. Performing them early in your training while you’re still fresh reduces the risk of incorrect form and allows you to perform at your best."

- Philip Stefanov, Certified Personal Trainer & Strength Training Coach

Are Isolation Exercises More Important Than Compound Exercises?

A gym coach teaching someone about isolation exercises

No, isolation exercises are not more important than compound exercises.

Both types of exercises should be implemented into a single workout program.

Compound exercises will build most of your muscle groups, and you will experience the most growth from them.

However, they aren’t always enough to build your body holistically, so implementing isolation exercises is crucial.

Isolation movements can help minimize muscle imbalances created by compound exercises, reducing the risk of potential injury, problems with posture, and more.

These exercises are more functional since they activate more muscle groups and joints [6].

These exercises are more functional since they activate more muscle groups and joints.

They also ensure your muscles work synergistically, which is excellent for creating new neural pathways in your brain and new movement stereotypes.

"Isolation exercises are mostly used in bodybuilding or for people rehabilitating from an injury or muscular imbalance. If you’re at an advanced stage of body training, then isolation movements can provide more definition to a specific area. It can also help to target areas of the body that are overlooked in compound exercises (those that build strength in more than one muscle group)."

- Phil Goulding, Nuffield Health Senior Personal Trainer

FAQs

What Is the Most Effective Leg Exercise?

The most effective leg exercise is a squat.

Squats are compound exercises that build the muscles in your lower body by following the squat movement pattern.

How Should I Separate My Leg Days?

You should separate your leg days into bending and squatting patterns. However, consider splitting between unilateral and bilateral leg days to develop the lower body holistically.

Should You Go Heavy on Isolation Exercises?

Yes, you should go heavy on isolation exercises. However, you should focus only on those exercises where multiple joints and muscle groups are used, such as a leg press.

What Muscles Should I Isolate?

You should isolate the quadriceps, hamstring, and gluteus muscles. Consider isolating adductors, abductors, and internal and external hip rotators for maximal muscle-building effects.

Is 4 Exercises Enough for Leg Day?

Yes, four exercises are enough for a leg day. Squatting, bending, lunging, and unilateral leg variations are enough to target all muscle groups and induce hypertrophy.

What Is the Best Leg Isolation Exercise?

The best leg isolation exercise is leg machine extensions.

Leg machine extensions isolate your quadriceps muscles, such as vastus medialis, vastus lateralis, vastus intermedius, and rectus femoris.

Based on my experience, not all leg extension machines are equal, and you need a durable, high-quality one with added functionalities.

That’s why you should read our guide on the best leg extension machines for 2023 to pick the best one that will suit your needs and home gym.

Let me know which leg isolation exercise is your favorite and why.


References:

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5744434/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4592763/
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4483447/
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3806175/
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6460214/
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8450457/
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