What Muscles Do Lunges Work?

Searching for an exercise that targets all of the lower body muscles? Look no further than the lunge, a strength training exercise that builds muscle, improves functional ability, burns calories, and increases the heart rate. This versatile exercise has many variations and is easy to modify or make more challenging. You can start with your body weight and begin adding dumbbells or even a loaded barbell, increasing weights as you progress each week. After reading below, you’ll understand what muscles lunges works and exactly how they are worked, as well as how to do lunges correctly, common mistakes to avoid, and the many benefits of incorporating this fundamental movement pattern into your routine. 

WHAT IS A LUNGE?

A forward lunge, also referred to as an anterior lunge, is a compound movement that targets pretty much your entire lower body. The exercise involves stepping forward with one leg and flexing the knee joints so both knees bend to 90 degrees, then pressing back up through your legs to a bilateral, tall-standing position. This requires your muscles to contract and balance. In addition, it isolates the muscles on your dominant and non-dominant sides, forcing them to work harder and helping you identify muscle imbalances that may exist.

Start this movement as a bodyweight exercise so you can master the technique. Improper form is a surefire way to cause an injury, so go slow at first, making sure your knee tracks over your second and third toes. Once you have the form down, you can introduce dumbbells to the movement. Continue increasing the weight and your glutes, quads, and hamstrings will keep growing. And, your core strength and stability will improve too!

LUNGE MUSCLES WORKED

The forward lunge works most of the lower body, whether as primary movers - the principal muscle known as the agonist - or synergists - muscles that assist in the movement.

Eccentric Phase (The Descent):

The primary muscles contracting in the forward lunge's eccentric - or descent - phase are the:

• Psoas (a hip flexor)
• Biceps femoris (the lateral hamstring muscle)
• Semimembranosus (the inner and largest of the three hamstring muscles)
• Semitendinosus (the middle hamstring muscle)
• Tibialis anterior (the muscle lateral to your shin bone)

The synergists working to assist these muscles include the:

• Iliacus (inner hip muscle)
• Tensor fascia latae (hip adductor and lateral muscle of the thigh)
• Gluteus Medius & Minimus (side glutes)
• Rectus femoris (the middle quadriceps muscle)
• Anterior adductors (upper-inner thigh muscles)
• Sartorius (the longest muscle in the human body, running from the upper side of the hip down to the inner side of the knee)
• Popliteus (major stabilizer of the knee)
• Gastrocnemius (the largest calf muscle)
• Gracilis (muscle of the inner thigh, crossing both the hip and knee joint)

Concentric Phase (The Ascent):

As the body moves upward to the anatomical position during the concentric contraction, the primary movers that create extension of the hip, knee and ankle joints are the:

• Gluteus maximus (the largest muscle of the glutes)
• Quadriceps (consists of 4 muscles that make up your anterior thigh)
• Soleus (muscle of the calf that lies below the gastrocnemius)
• Gastrocnemius

The synergists during the concentric phase of the lunge are the: 

• Biceps femoris long head (hamstring muscle head that connects to your pelvis and acts on the hip extension)
• Gluteus Medius & Minimus
• Peroneus (Fibularis) longus (lateral compartment of the lower leg)
• Peroneus (Fibularis) brevis (lateral compartment of the lower leg)
• Tibialis posterior (deep muscle of the inner lower lega)
• Flexor hallucis longus (posterior lower leg muscle involved in moving the big toe and foot)
• Flexor digitorum longus (deep posterior muscle of the lower leg)
• Plantaris (long thin posterior muscle of the lower leg that runs from your knee to your heel)

Because the lunge works so many lower-body muscles, it helps prevent one leg muscle - often the quadriceps, as it is susceptible to becoming tight and overactive - from becoming dominant. Balanced lower body muscles prevent or repair knee issues, back pain, and poor posture.

HOW TO DO A LUNGE CORRECTLY:

1. Start in the anatomical position with your feet shoulder-width apart. If you’re not using weights, place the hands on the hips. Before moving the lower body, ensure your upper body is stabilized by depressing and retracting the shoulder blades and engaging your abdominals to stiffen the spine.
2. Lift one foot off the floor and swing it forward, taking a large step. As your foot contacts the ground, shift your body weight into the forward foot firmly planted on the floor. Avoid any tilting or swaying during the movement. Ensure your shoulders remain down and back, spine stiff, and the trunk upright.
3. Drop your hips toward the floor and continue lowering until the front thigh is parallel with the floor and the shinbone is leaning forward slightly. At the same time, create flexion, or a forward bend, at the hips keeping your back flat. Both knee joints bend to 90 degrees.
4. Pause for a second, holding this position.
5. To move back to the starting position, the leg that is forward must push off the ground using the gluteus and quadriceps muscles to return to the starting position.
6. Aim for three sets of 15 repetitions on each side. If you’re new to this exercise and notice you are losing good form as your body fatigues, begin with two sets of 10 to 12 repetitions and gradually increase this.

BIOMECHANICS OF THE MOVEMENT (AND HOW THE MUSCLES ARE WORKED)

Eccentric Phase: The eccentric phase of the forward lunge, which is the descent, requires triple flexion of the hip, knee, and ankle. Triple extension of the same three joints is necessary to return the body to the anatomical position during the forward lunge's concentric - or ascent - phase. The psoas, biceps femoris, semimembranosus, and semitendinosus contract to move the lower body into flexion. At the bottom of the descent, these muscles, along with the gluteal muscles, isometrically contract as the body pauses briefly before starting the ascent.

Concentric Phase: As the body moves back to the anatomical position, in which the body faces forward with legs hip-width apart, toes facing forward, the gluteus maximus concentrically contracts as the prime mover of hip extension, which must occur to return the body to standing. In addition, the quadriceps muscles are the prime movers of knee extension, a movement that enables the legs to straighten and returns the lunging leg to its starting position. As the forward foot pushes off the ground, it propels the leg back to the beginning position as the primary movers of extension concentrically contract.

In addition to the muscles mentioned above, there are many stabilizing muscles working to keep you balanced through both the eccentric and concentric phase. The main stabilizers are your hip abductors/adductors and the muscles of your lower legs.

Note: In the forward lunge, movement should be slower in the eccentric phase as the hip, knee, and ankle joints move into flexion and faster in the concentric phase as power returns the forward leg to the standing position.

Plane of Motion: Since this exercise involves flexion and extension, the forward lunge occurs in the sagittal plane and transverse axis. Static equilibrium, which is when the body is stationary and the external forces and torques acting on the body sum to zero, is achieved in the forward lunge when the body is in the anatomical position before starting the exercise. 

5 VARIATIONS OF LUNGES & MUSCLES USED:

Let's look at several variations lunges and how they alter the muscles emphasized...

Note: You can use various equipment for these lunges, just like you can a forward lunge.

1. Reverse lunge:

Increase your stability, isolate muscle imbalances, and build your glutes, quad, and hamstring muscles simultaneously while performing the reverse lunge. This movement is truly just the reverse movement of the forward lunge - hence, the name. This exercise works the same muscles as the forward lunge, focusing on the gluteus maximus, hamstrings, and quadriceps. The reverse lunge also works the adductor magnus and the two main calf muscles, the soleus and gastrocnemius. If you have quads that are overworked or dominant, opt for the reverse lunge over the forward one. The momentum you have to generate to return the back leg forward to the start position helps activate the glute and hamstring muscles, preventing all the work from falling to your quads.

How To:

1. Stand straight with feet shoulder-width apart, stabilizing your core muscles. 
2. Take a big step backward with one foot. Aim for about one and a half times the stride length you normally take. Make sure your torso remains upright throughout the movement.
3. Make sure the foot that moves backward lands on the ball of the foot, followed by the heel.
4. Bend the knee that remained stationary and lower the knee of the back leg to 90 degrees.
5. Push through the heel and midfoot of the front leg, so that you’re pushing upward as you bring your back leg forward to the starting position. Switch legs and repeat on the other side.
6. Aim for three sets of 15. As you increase dumbbell weight, you may find that you can’t do this many to start. Work up to it each week. If you can't do a minimum of two sets of 10 to 12, reduce your weight.

2. Walking lunge:

Not only does a walking lunge hit all of the major lower body muscles, but it's also a functional exercise, meaning it mimics activities from your daily life, such as stepping forward to grab something, standing, or sitting. Functional activities such as this are great as their goal is to improve the fluidity of real-life movements. The unilateral movement that the walking lunge emphasizes is great for isolating and addressing muscle imbalances that might exist on the non-dominant and dominant sides.

How To:

1. Stand straight with feet shoulder-width apart. Place your hands on your hips if you are not holding dumbbells. Keep your torso upright and make sure your core is engaged. Rotate the shoulders back.
2. Take a wide step forward with one leg, making sure to place the weight on your heel.
3. Bend the knee of the forward leg and lower your back knee toward the floor, lowering down until the thigh is parallel to the floor in a lunge position. Pause for 1 to 2 seconds.
4. Press through the heel, keep the forward leg still, and then swing your back foot forward, planting it approximately 2 feet in front of your other foot. Repeat the same movement on this leg as you did the first time. Bend the knees to 90 degrees, pausing once the forward thigh is parallel to the floor.
5. Continue to repeat this movement, walking forward as you lunge, alternating legs.
6. Do 12 to 15 reps on each leg. Aim for three sets.
   

3. Side Lunge:

The side lunge targets the quads, glutes, and hamstrings, but also adds in a few additional muscles on the inner and outer thighs: adductor longus, adductor brevis, and adductor magnus, which work with the quads and hamstrings to control the movements of the knee and hips on the lunging leg. Bonus points for the adductors on the trailing leg, because they get a nice stretch during the exercise. The side lunge pairs well with the walking lunge in a fitness routine as it ensures you're strengthening your muscles forward and backward and side to side. In addition, if you enjoy playing a sport, even recreationally, that requires side to side movements, such as basketball, tennis, baseball, and football, the side lunge will help strengthen the muscles needed for those activities.

How To:

1. Stand with your feet shoulder-width apart pointing forward. Keep the torso straight.
2. Keep one foot planted and lift the other, taking a big step to the side. Continue to keep your torso straight.
3. Lower until the knee of the leg that stepped outward is bent to 90 degrees. The stationary leg should remain straight.
4. Place all the weight into the lunging leg as you push through the heel to bring it back to the starting position. Repeat on the other side. This is one rep.
5. Aim for three sets of 12 reps.

4. Static Lunge:

The static lunge, also called the split squat, is a great introductory movement, and mastering this exercise before progressing into the other lunges will ensure your form is perfect. When comparing split squats vs lunges, both target the glutes, quadriceps, and hamstrings. Be sure to place most of your weight on the front leg, and rely on the back limb to balance and stabilize. You can make this more challenging by adding weights, speeding up the tempo, or holding for five seconds at the bottom of the descent.

How To:

1. Start in a split stance, with one foot forward and the other back. Keep your torso straight, and engage the abdominal muscles. 
2. Lower your hips to the floor by bending the knees and creating flexion at the hips. Continue lowering until your knees bend to 90 degrees. Pause here for a moment.
3. Press through the heel that is forward, returning to the starting position.
4. Do 12 to 15 reps before switching sides. Aim for three sets.

5. Curtsy Lunge:

A strong gluteus medius is the name of the game for the curtsy lunge. And while your glute muscles are going to put in the most work, this move also strengthens the hip adductors, quads, and hamstrings. Since the curtsy lunge targets strengthening the glute muscles, it contributes to good posture, preventing and relieving back and knee pain, and discouraging the quadriceps from becoming overly dominant (they tend to try to take over). This exercise is also great for helping with hip stabilization and strengthening your inner thighs, an area that can be hard to target through many traditional lower-body exercises. Use your bodyweight, one dumbbell, or a pair of dumbbells. You can decide how challenging to make it.

How To:

1. Stand with your feet shoulder-width apart. Place your hands on your hips. 
2. Place the majority of your weight on the foot that will remain stationary, take a big step back with your other leg, crossing it behind the stationary one. Bend the knees, lowering the hips until the thigh that has remained stationary is parallel to the floor. The torso must remain upright, and the hip and shoulders should remain facing forward. 
3. Return to start by pushing through the heel of the stationary leg to straighten it. Bring the foot that is behind to the starting position, and repeat on the other side.
4. Aim for three sets of 12 reps.

COMMON MISTAKES WITH LUNGES

Once mastered, the forward lunge is a powerhouse move that should become a staple exercise in your fitness regimen. After all, it is a foundational movement pattern.

However, technique and good form are everything when it comes to the lunge, so when first learning it, go slowly and look in a mirror to keep an eye on your form.

Here are some common mistakes to avoid:

• A very common mistake is not stepping forward enough so that your knees can't bend to 90 degrees. This mistake throws the whole move off and makes it so that none of your lower-body muscles are fully activated.
• Stagger your feet slightly so they are not in line with each other. If not, it can cause instability in the movement.
• Your front foot needs to be completely stable, and watch out for the front knee collapsing or turning in. The back ankle remains rigid, so the foot doesn’t turn, resulting in toes facing outward.
• Keep your core and back stabilized and your trunk as upright as possible. You should not see rounded shoulders or your upper body leaning forward in this movement.
• Your chin should be parallel to the floor. Avoid having it stick out during the movement as it creates unnecessary stress on the upper spine and throws off your alignment.
• Your front and back knees need to bend simultaneously - do not bend one without bending the other.
• Your front knee should not go past your toes. Finally, keep your glutes tucked underneath you, and do not arch the lower back.

BENEFITS OF LUNGES:

• Lunges activate all of the major muscle groups in the lower body.
• The muscles in your core and back stabilize you throughout the movement, meaning the lunge also works the important stabilizer muscles in the upper body.
• Lunges are adaptable. You can modify them to only using bodyweight, or even not sinking as low in the lunge. Alternatively, you can continue increasing the challenge of the exercise by adding dumbbells or a barbell and increasing their weight each week.
• Lunges are functional exercises that improve your stamina and fluidity for day-to-day activities and sports.
• The lunge increases your heart rate, burns calories, and builds muscle.
• Lunges can be a warm-up, part of a HIIT or cardio routine, or included in a strength-training workout.

This versatile exercise can strengthen and stretch the body while training your lower body muscles to handle everyday activities and mimic important sports movements. The options with lunges are also endless: add weights to make them more challenging, increase the tempo to get the heart rate up, or add a few different variations to make sure you’re emphasizing all of the major lower-body muscle groups. At least one lunge variation needs a place in your fitness routine.

While lunges are great for maintaining knee strength, they can be hard on the knees for people who already have issues. If that's the case for you, here are the best lunges alternatives for bad knees.

Related: What Muscles Does a Rowing Machine Work?