8 Best Leg Isolation Exercises (Target Each Muscle Group)

Christiana Mikesch, CPT
Published by Christiana Mikesch, CPT | Senior Coach
Last updated: April 30, 2024
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You must incorporate isolation exercises to have the best possible muscle-building effects for a single or small muscle group.

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

I tested more than 30 isolation exercises and singled out those I 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 are leg extension machine, seated hamstring curl, lying hamstring curl, calf raises, single leg extensions, nordic hamstring curl, hip adduction (machine), and one-legged cable kickback.
  • Isolation exercises can help fix muscle imbalances, which can occur when focusing solely on compound exercises, increasing the risk of injury.
  • Isolation exercises can lead to high levels of muscle activation in the targeted muscle group, often exceeding 70-80% of maximal voluntary contraction (MVC) values.
  • In my personal opinion, integrating isolation exercises into your fitness routine is a key element for achieving well-rounded muscle development and preventing imbalances.

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

In my years as a fitness coach, I've found the leg extension machine to be a go-to for effectively targeting the quadriceps.

It positions the body to maximize force exerted by the quads, with weight placement enhancing leverage for effective muscle engagement.

This exercise primarily involves knee flexion, working key muscles like rectus femoris, vastus lateralis, medialis, and intermedius.

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.

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

From my personal training experience, seated hamstring curls have been excellent for clients focusing on their posterior chain, particularly the hamstrings.

These curls are particularly beneficial for early-stage hamstring rehabilitation, as they don't require an athletic stance.

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

Having tried both seated and lying hamstring curls myself, I've noticed the lying version offers a unique biomechanical challenge due to gravity's impact, making the exercise more demanding.

Commonly utilized in early rehabilitation stages, it's less functional for general lower body training in healthy individuals.

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

Through my fitness journey, I've seen significant calf muscle development with regular calf raises.

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

Based on my experience, single leg extensions on the leg extension machine have been crucial in the recovery phase of many athletes I've coached.

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

As a coach, I've incorporated Nordic hamstring curls in many workout routines, finding them highly effective for enhancing the posterior chain's strength.

This bodyweight exercise involves using the hamstrings to control the descent of the body.

To increase difficulty, incorporate weight plates in the exercise progression.

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)

From my training sessions, I've seen machine hip adductions significantly improve adductor muscle group strength in clients, including adductor magnus, longus, and brevis, as well as the gracilis and obturator externus.

This isolation exercise is crucial for injury prevention and enhances stability in 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

In my professional experience, one-legged cable kickbacks have proven to be one of the most effective exercises for isolating and strengthening the gluteal muscles, including the gluteus maximus, minimus, and medius, and also engage hamstrings like the semimembranosus, semitendinosus, and biceps femoris.

Ideal as an accessory lift following compound exercises targeting similar muscles, these kickbacks with a cable machine enhance functionality, offering significant benefits for 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, according to the Asian Journal of Sports Medicine [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. 

Focusing solely on compound exercises like squats predominantly builds the quadriceps, often neglecting simultaneous hamstring development.

This can lead to imbalances between the front (anterior) and back (posterior) muscle chains, increasing injury risk. Incorporating isolation exercises is key to preventing these imbalances, and they also complement compound movements to enhance overall 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

Compound exercises, involving multiple joints, can be demanding and may lead to injuries, especially during high-intensity workouts or max lifts.

For those recovering from such injuries, isolation exercises are a practical alternative.

These exercises allow you to work around the injured area, avoiding further strain on the affected muscles or joints. Implementing isolation exercises during recovery helps maintain overall fitness and prevents muscle atrophy, ensuring continuous physical activity without exacerbating the injury, according to the Sports Health [4].

Which Isolation Exercises Can I Do?

A woman warming up for isolation exercises

All isolation exercises can be beneficial, but your choice should align with your fitness goals. These exercises are particularly effective for focused muscle growth, injury prevention, and complementary lifts in a workout regimen. For optimal muscle hypertrophy, aim for 6-12 reps across up to 4 sets in each isolation exercise.

Expand your leg workout regime by including specific isolation exercises for often overlooked areas such as the traps and forearms, where a slow and controlled motion can lead to significant muscle development.

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.

While isolation exercises are beneficial, it's important to be aware of their potential risks and drawbacks, such as the possibility of muscle imbalances and the importance of maintaining correct form to avoid injuries.

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].

When programming your workout, two key rules should guide your exercise selection.

First, prioritize compound exercises at the beginning of your session. These exercises demand more energy and focus, as they engage multiple muscle groups simultaneously. Avoid doing them when fatigued to prevent the risk of injury.

Second, complement compound movements with related isolation exercises. For instance, after squats (a compound exercise), you can include isolation exercises like hip thrusts or leg extensions, targeting the same muscle groups.

This strategy ensures a balanced workout, enhancing overall muscle development while reducing the risk of 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

Isolation exercises are not more important than compound exercises, but they are a necessary complement to any workout regimen.

Compound exercises are key for overall muscle development, contributing to significant growth across multiple muscle groups.

However, for holistic body development, incorporating isolation exercises is essential.

They specifically target muscles that may be underworked in compound movements, helping to correct muscle imbalances, reduce injury risks, and improve posture.

These exercises are more functional since they activate more muscle groups and joints, according to the Frontiers in Physiology [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.


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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About The Author

Christiana Mikesch, CPT
Senior Coach
Christiana Mikesch, CPT is a personal trainer and author with contributions to publications like the Chicago Tribune and Yahoo. She emphasizes a holistic approach to weight loss, combining an energy-fueling diet, goal-oriented workouts, and daily habits. Her approach avoids short-term goals and fosters a lifelong commitment to health and well-being.
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Lisa Lorraine Taylor, BSc, CPT
Staff Writer
Lisa Lorraine Taylor, BSc, CPT holds a BSc degree in Holistic Nutrition from Clayton College of Natural Health and is the owner of Taylor Made Fitness. Her philosophy centers on cutting through the hype and misinformation surrounding dietary supplements, focusing instead on practical, science-backed strategies for health and weight loss.
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Dr. Harshi Dhingra, MBBS, MD is a published peer-reviewed author and renowned physician from India with over a decade of experience. With her MBBS from Bharati Vidyapeeth and an MD from Rajiv Gandhi University, she actively ensures the accuracy of online dietary supplement and medical information by reviewing and fact-checking health publications.
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