The side plank is an isometric core exercise performed on one forearm with the body held in a straight line on its side. It trains the obliques and the deep lateral stabilizers to resist sideways collapse, making it one of the best movements for building anti-lateral-flexion strength. Because it requires no equipment and is easy to regress or progress, the side plank fits any program from rehab to advanced core training.
Muscles Targeted
- Primary: Obliques (internal and external), quadratus lumborum
- Secondary: Gluteus medius, transverse abdominis, rectus abdominis
- Tertiary: Shoulder stabilizers (deltoid, rotator cuff), adductors
Starting Position
Lie on your side with your legs extended and stacked on top of each other. Place your bottom forearm flat on the floor with the elbow directly beneath your shoulder, forearm pointing forward. Stack your hips and shoulders vertically, engage your core, and rest your top arm along your side or on your hip.
Execution Steps
- Brace your core and press your bottom forearm into the floor to create tension
- Lift your hips off the ground until your body forms a straight line from head to feet
- Stack everything- keep your top shoulder, hip, and ankle aligned in one vertical plane
- Hold the position while breathing steadily and keeping the hips high
- Avoid sagging or rotating- maintain a rigid, neutral spine throughout the hold
- Lower with control after the target time, then repeat on the opposite side
Form Cues
- Keep a straight line: Maintain a head-to-heel line with no sag at the hips or piking upward
- Stack the shoulder over the elbow to protect the joint and maximize stability
- Squeeze the bottom glute and oblique to keep the hips lifted
- Keep the neck neutral by looking straight ahead, not down at the floor
- Breathe continuously rather than holding your breath during the hold
Common Mistakes
- Sagging hips: Letting the hips drop removes tension from the obliques and stresses the lower back.
- Rotating the torso: Allowing the chest or hips to roll forward reduces lateral core engagement.
- Elbow out of position: Placing the elbow ahead of or behind the shoulder strains the joint.
- Holding the breath: Bracing without breathing limits how long and how safely you can hold.
- Looking down: Dropping the head breaks neutral spine alignment.
Variations
- Knee side plank: Performed from the bottom knee to reduce difficulty for beginners
- Side plank with hip dips: Lower and raise the hips for a dynamic oblique challenge
- Side plank with leg raise: Lift the top leg to add hip and core demand
- Star side plank: Extend the top arm and leg for an advanced stability test
- Side plank with reach-through: Thread the top arm under the torso and back out for rotation control
Tips for Progression
- Increase hold time: Add 5-10 seconds per set as your endurance improves
- Add reps or sets: Progress from one to two or three holds per side
- Add movement: Introduce hip dips or leg raises once static holds feel easy
- improve the feet: Raise your feet on a bench to increase the lever and load
Training Notes
Include side planks in your core training two to three times per week, working both sides equally to prevent imbalances. Beginners can start with 15-20 second holds and build toward 45-60 seconds per side. Because the side plank is an anti-lateral-flexion exercise, it pairs well with anti-extension work like the front plank and anti-rotation work like the Pallof press for complete core development. Quality of position matters more than duration - end the hold once your form breaks rather than pushing through a sagging position.