Side Plank Benefits, Form, and Muscles Worked

Plank variations are excellent for building core strength and targeting multiple muscle groups throughout the upper body. The side plank is a variation that helps build lateral stability and targets obliques. Here’s how to perform the side plank with perfect form to reap maximum benefits, explaining how the side plank targets each primary target muscle group. 

How to Perform Side Planks With Proper Form

1. Lie on side on exercise mat with legs extended and stacked on each other.
2. Position elbow directly under shoulder, with forearm resting on the mat perpendicular to body.
3. Engage core by pulling navel towards spine, press forearm firmly into the mat.
4. Lift hips off mat, creating a straight line from head to 1heels.
5. Keep body straight, avoiding sagging or rounding of the lower back.
6. Extend top arm toward ceiling, or place on hip. This is starting position. 
7. Keep neck relaxed and aligned with spine, avoiding excessive strain.
8. Maintain a steady, controlled breath throughout the exercise.
9. Hold the position for the desired duration, gradually increasing with strength.
10. To release the side plank, slowly lower hips to the mat and rest briefly before repeating on the other side.

Check out this video from Howcast for a visual demonstration of the proper setup, starting position, and form for a side plank.

How to Do a Side Plank | Ab Workout

Side Plank Form Tips

1. Keep both hip points facing forward
2. Keep the chest open and shoulders neutral
3. Squeeze the obliques
4. Keep breathing
5. Wear supportive shoes

Keep both hip points facing forward

Keep both hip points facing directly forward to align the body and target the correct muscle groups. When the core starts to fatigue, there can be a temptation to rotate the body, causing the bottom hip to round inward or the upper hip to splay out. 

Keep the core engaged and the body in a straight line. Try easier variations, such as resting the lower body on the knees rather than the feet, until strength increases. 

Keep the chest open and shoulders neutral

Spread the shoulder blades to prevent the shoulders from rolling forward or pulling back too far. Keep an open posture and torso without pinching the scapula together, which can cause the spine to flex and lose its neutral alignment. If maintaining the proper side plank position with the feet stacked is too difficult, try an easier progression by dropping to the knees or using the top leg as a kickstand to add stability. 

Squeeze the obliques

Avoid dumping all the weight into the supporting arm and shoulder. Actively contract the muscles in the side of the torso to maintain a straight line from head to toe. Keep this contraction throughout the side plank, and don’t let the hips sag. 

Keep breathing

Some people accidentally hold their breath while tensing their core and obliques and focusing on form. Keep tension in the torso, but take normal breaths to avoid dizziness or lack of oxygen while holding the plank position. Build up oblique strength slowly by gradually increasing the duration of the side plank. 

Wear supportive shoes

The traditional side plank usually has the feet stacked on each other to keep the body straight. Avoid putting excess pressure on the outer edge of the bottom foot by wearing good shoes and pressing the shoe’s sole towards the ground to create a stable foundation without creating foot pain.

Common Side Plank Mistakes

1. Letting the hips drop
2. Losing alignment of the head and neck
3. Arching the lower back 
4. Elbow not stacked under the shoulder
5. Bending the knees

Letting the hips drop

Keep squeezing the supporting hip, oblique, and outer thigh to keep the hips high. The body should form a straight line from head to heels, with rigidity and tension throughout the body to get the maximum benefits.

Losing alignment of the head and neck

The neck and head are part of the spine and need to be kept neutral and aligned to ensure the side plan is safe and effective. Avoid crunching or craning the neck, keep gaze down or straight ahead, and relax the upper traps and neck muscles as much as possible.

Arching the lower back

Letting the lower back arch in a side plank position shifts the strain to the wrong muscle groups and could lead to back or shoulder pain. Keep squeezing the core and the glutes to keep the pelvis, hips, and spine straight, aligned, and supported. 

Elbow not stacked under the shoulder

Depending on the side plank variation, the hand or elbow of the supporting arm should always stay directly under the shoulder joint. Placing it above or below the shoulder can strain the delicate joint and extend the torso, throwing off the alignment and making the exercise less effective at hitting the target muscle groups. 

Bending the knees

One helpful side plank variation involves bending and planting the bottom knee for added support and stability. However, avoid doing a traditional side plank with the knees bent to get the most out of the exercise. The side plank works best when there is tension throughout the body, and bending the knees can compromise the proper side plank position. Squeeze the abs, hips, glutes, and quads to keep the legs locked and stable. 

Side Plank Benefits

1. Targets the core without straining the back
2. Strengthens the spinal stabilizers
3. Addresses muscular imbalances 
4. Improves balance and coordination 
5. Accessible and versatile
6. Increases muscular endurance
7. Works muscles throughout the entire body 

Targets the core without straining the back

Side planks are an effective compound core strengthening exercise that targets the hips, abs, obliques, glutes, shoulders, and legs to improve balance and stability throughout the body. Unlike many other ab exercises, like crunches and situps, side planks place minimal stress on the lower back. Side planks are an excellent choice for people who experience neck or back pain in other core exercises. 

Strengthens the spinal stabilizers

Side planks target the deep spinal stabilizing muscle quadratus lumborum (QL), which can help prevent back pain and injuries. Crunches and situps mainly target the rectus abdominis, the most visible part of the abs. However, the deep core muscles are vital for a strong, stable, and supported spine.

Addresses muscular imbalances 

Side planks are a unilateral exercise, training one side at a time. As long as you always perform an even amount of work for the left and right side, the side plank is a great way to address uneven musculature and strength to help improve functional fitness in everyday life. 

Improves balance and coordination 

The core is the foundation for maintaining balance and stability during everyday activities like walking and carrying items. Strengthening the center of gravity with functional exercises like the side plank helps to prevent falls and injuries, developing confidence and safety to challenge the body in new and versatile ways.

Accessible and versatile

Side planks can be done anywhere without any special equipment or access to a gym. Even extremely busy individuals can find time to practice the side plank, whether during a commercial break while watching TV or between conference calls at work. A little goes a long way with side planks, and there are side plank variations to suit every experience level.

Increases muscular endurance

Isometric holds are a great way to build muscular endurance, especially for some smaller and often neglected deeper core muscles throughout the torso. With consistent practice, many people can see their endurance in the side plank improve quickly, boosting confidence and motivation.

Works muscles throughout the entire body

The side plank is a time and energy-efficient exercise that targets multiple muscles in the upper but also the outer quads, glutes, and calves. For time-poor individuals, the side plank is a great way to build stability and strength throughout the body without spending hours in the gym.

Side Plank Muscles Worked

1. Internal and external obliques
2. Transverse abdominis
3. Rectus abdominis
4. Quadratus lumborum
5. Glutes
6. Calves
7. Outer quads

Internal and external obliques

The side plank is a highly effective exercise for the internal and external obliques. The oblique muscles stabilize and align the torso in the side plank’s side-lying position, supporting the body on one forearm while lifting the hips off the ground. This isometric hold challenges the muscles to resist lateral flexion, promoting strength and endurance. Check out our list of the best ways to build stronger obliques for more effective core strengthening exercises. 

Transverse abdominis

The side plank exercise targets the transverse abdominis, a deep core muscle. By assuming a side-lying position and squeezing the core, the transverse abdominis works isometrically to stabilize and lift the torso. During an isometric side plank hold, the transverse abdominis contracts to stabilize and keep the spine aligned.

Rectus abdominis

The primary focus of the side plank is the obliques. However, the rectus abdominis also stabilizes the torso during the isometric hold. The rectus abdominis, or the “six-pack” portion of the core, is recruited to maintain proper alignment and prevent the back from rounding or sagging. For effective rectus abdominis exercises, check out this workout plan to help build six-pack abs.

Quadratus lumborum

The side plank is an effective way to strengthen and activate the Quadratus lumborum, a deep muscle located on the sides of the lower back. In the side plank, this muscle helps stabilize the pelvis and spine as the hips lift off the ground to prevent excessive side bending.

Glutes 

The gluteus medius, located on the outer side of the hip, helps maintain hip stability during the side plank. It contracts isometrically to help prevent the top hip from dropping or rotating backward. The gluteus maximus is also engaged in the side plank. Although not the primary target, it assists in hip extension and stabilization, working isometrically to support the pelvis and keep the body in a straight line. For more effective glute builders, here is a list of the best gym machines for building the glutes.

Calves

The calf muscle, or gastrocnemius muscle, makes up the bulk of the posterior lower leg musculature. During a side plank, the calves play a synergistic role in keeping the lower legs lifted and engaged against gravity in the lifted side-lying position. 

Outer Quads

During a side plank, the outermost part of the quadriceps engages isometrically to maintain a neutral, straight line with the upper and lower body. The outer quad of the leg closest to the ground has to contract to keep the hips high and engage the abdominals and obliques. Check out our list of the best outer quad exercises for more ways to build more muscular outer thighs.

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About Emma Lennon

Emma is a Health Science graduate, qualified personal trainer, and writer. She has over ten years of experience in the health, community development, and communications sectors. She is passionate about making reputable information about health, fitness, and resistance training accessible to all.

Emma loves building her own functional strength and fitness outside of work with various training styles, from weightlifting to calisthenics, yoga, and dancing. She advocates for the powerful potential of exercise to improve physical, mental, and emotional health and well-being.