MariposasHow to Do the Side Plank
By Zachary, builder of Mariposas · Reviewed against published exercise-science sources (references)
· Last updated June 2026
The side plank earns its place in core training because it targets the lateral line of the trunk, specifically the obliques, in a way that almost nothing else replicates under pure anti-lateral-flexion demand. Where a crunch or leg raise loads the abs through flexion, the side plank forces the obliques to resist collapse against gravity for the entire duration of the hold, which is a fundamentally different stimulus. That sustained isometric tension is what makes this movement particularly effective for building the kind of lateral stiffness that transfers to heavy carries, overhead pressing, and rotational sport movements. If you want to track your side plank holds and progressions alongside the rest of your training, the Mariposas app lets you log it for free.
How to do it
- Lie on your side on a mat with your forearm flat on the ground, elbow directly beneath your shoulder, and your feet stacked on top of each other so your body forms one straight line from ankle to ear.
- Before you lift, brace your abs hard as if someone is about to press a thumb into your navel, and squeeze your glutes so your hips don't sag the moment you leave the floor.
- Press your forearm into the ground and drive your hips straight up so your body forms a rigid diagonal plank, with only your forearm and the outer edge of your bottom foot in contact with the mat.
- Check that your hips are not piking upward or sagging downward; your spine should be neutral, not curved in either direction, and your neck should be a natural extension of that line.
- Stack your top hand on your hip or extend it toward the ceiling to open the chest; avoid resting it on your top thigh, which tends to encourage a forward lean that reduces oblique demand.
- Breathe steadily throughout the hold by taking shallow, controlled breaths; holding your breath entirely causes a pressure spike and also shortens how long most people can maintain good position.
- Hold for the target duration, then lower your hips under control back to the mat rather than collapsing, and repeat on the opposite side before counting either as a completed set.
Form cues
- Ear, shoulder, hip, ankle: one line.
- Drive the floor away with your forearm.
- Squeeze glutes, ribs down.
- Top hip stacked directly over bottom hip, not rotated forward.
- Breathe shallow, stay tight.
Common mistakes
- Letting the hips sag toward the floor is the most common error and it shifts the load away from the obliques and onto the shoulder joint, so cue yourself to push the floor away and recheck your hip height every few seconds.
- Rotating the torso forward so the chest faces the floor rather than the wall turns the side plank into something closer to a modified front plank and almost completely eliminates the lateral oblique challenge, so keep that top shoulder pulled back and stacked.
- Craning the neck upward or dropping the chin to the chest breaks the spinal line and creates unnecessary cervical tension; keep your gaze neutral and your head in line with your spine.
- Placing the feet in a split stance, one foot in front of the other, can feel easier but it actually changes the base of support and reduces the anti-lateral demand the obliques face, which limits the training effect if the goal is lateral stability.
- Holding too long with broken form instead of cutting the set short; a ten-second hold in perfect position trains the obliques far more effectively than forty seconds of sagging, rotating, and compensating.
Why do the Side Plank?
- The obliques trained here are the primary muscles that resist lateral bending of the spine, so stronger obliques from consistent side plank work tend to show up as better control during heavy barbell carries and single-arm loaded movements.
- Because the abs are also engaged to prevent spinal rotation and extension during the hold, the side plank builds the kind of multi-directional trunk stiffness that translates directly to compound lifts where the core must stay rigid under asymmetric load.
- The exercise requires zero equipment and almost no space, making it practical for bodyweight-only training days, travel, or sessions where heavier core loading is not available.
- The isometric nature of the movement creates high oblique tension without any spinal flexion, which is relevant for people who want core work that does not involve repeated bending of the lumbar spine.
- Improving the side plank hold often correlates with better lateral balance and hip stability because the glutes and hip abductors on the lower side must also work to keep the body from collapsing.
Side Plank variations
- Knee-Down Side Plank
- Performed with the bottom knee on the mat instead of the foot, this reduces the lever arm significantly and is a practical starting point for anyone who cannot yet hold a full side plank for at least ten seconds with neutral alignment.
- Side Plank with Hip Dip
- From the full side plank position the hips are lowered toward the mat and raised back up for reps, adding a dynamic oblique contraction on top of the base isometric demand and bridging the gap toward weighted lateral work.
- Side Plank with Top Leg Raise
- Lifting the top leg while holding the plank adds a hip abductor challenge and further destabilizes the position, making the obliques work harder to prevent rotation; useful once the static hold is well-controlled for thirty or more seconds.
- Weighted Side Plank
- A weight plate or dumbbell rested on the top hip increases the load the obliques must resist and is commonly used by lifters who have outgrown bodyweight holds as a strength stimulus rather than an endurance one.
How to program it
Side planks appear most often toward the end of a training session as a core finisher, after the main compound work is done, since pre-fatiguing the obliques before heavy squats or deadlifts is generally not the goal. Hold durations typically range from fifteen to sixty seconds per side depending on training level, and many coaches program them in two to four sets with the aim of accumulating total time under tension across the week. Some programs use them as a daily low-fatigue practice rather than a once-per-week accessory, since the isometric bodyweight nature of the exercise allows for frequent exposure without significant recovery cost. Progressing by adding hold time before adding a harder variation is the standard approach most practitioners follow.
Side Plank alternatives
FAQ
- What muscles does a side plank work?
- The primary muscles are the obliques and abs. The obliques do most of the anti-lateral-flexion work, resisting the pull of gravity trying to collapse the hips toward the floor, while the abs engage to prevent spinal rotation and extension throughout the hold.
- How long should I hold a side plank?
- There is no universal answer, but most people start building from fifteen to twenty seconds and work toward sixty seconds per side before moving to a harder variation. The quality of the position matters far more than the clock, so a short hold with a neutral spine is better training than a long hold with sagging hips.
- Why do my obliques cramp during a side plank?
- Cramping usually means the obliques are being asked to sustain a contraction they are not yet conditioned for. Starting with the knee-down regression, keeping initial holds short, and building volume gradually over several weeks tends to resolve this as the muscle adapts.
- Is the side plank better than the regular front plank?
- They are not competing exercises. The front plank stresses anti-extension and the anterior core more directly, while the side plank is the primary loaded position for lateral trunk stability and oblique strength. Many programs include both because the demands are genuinely different.
- Can I do side planks every day?
- Many people do, without issue. Because the exercise is bodyweight and isometric, the recovery demand is low compared to weighted movements. Daily practice at moderate volumes is common in programs focused on building core endurance, though soreness in the first week or two is normal as the obliques adapt.