Side Plank Progressions: Building Lateral Core Strength Step by Step
A side plank trains the muscles down the side of your trunk to stop your body sagging sideways towards the floor. The best way to build it is in stages: start on your knees, hold good positions for short sets of 15 to 20 seconds, and only move to a harder version once you can do three clean sets on each side. Then lengthen the lever, raise the feet, add movement or add load. Most people stall because they jump to the full version too early and spend every set with their hips drifting backwards, which trains the wrong thing.
What the side plank actually trains
The front plank asks your trunk to resist arching. The side plank asks it to resist bending sideways. The obliques, the deep muscles of the lower back on the side nearest the ceiling and the glute muscles on the outside of the hip all work together to hold you level. Your supporting shoulder has to stay stacked and stable throughout.
That lateral strength is quietly useful. It is what keeps your pelvis level when you stand on one leg, climb stairs two at a time or carry a heavy bag in one hand down Archway Road. It matters for running, racquet sports and anything single-leg in the gym. It is also one of the core qualities that rarely gets trained, because crunches and front planks do not ask for it.
Setting up a good side plank
- Lie on your side with your elbow directly under your shoulder and your forearm pointing forwards. Not out in front, not tucked behind.
- Stack your body. Hips on top of each other, shoulders on top of each other. Your head lines up with your spine.
- Brace lightly as if someone is about to tap your stomach, and squeeze your glutes so your hips are pushed forwards rather than sitting back.
- Lift your hips until there is a straight line from head to knees (on the knee version) or head to ankles (on the full version).
- Push the floor away with your forearm so you do not sink into your shoulder.
- Breathe. Slow, quiet breaths through the nose. If you have to hold your breath to stay up, the version is too hard for now.
The single best check is a mirror or a phone propped up in front of you. From the front you will see whether your top hip has rolled forwards or backwards. From above you should look like a straight plank of wood, not a banana.
The progression, stage by stage
The table below is the order I use with most clients. Stay at a stage until you can hold three sets of the target time on each side with no sag, no rotation and steady breathing. For most people that is two to four weeks per stage, trained two or three times a week.
| Stage | Version | Target before moving on |
|---|---|---|
| 1 | Side plank on knees | 3 x 30 seconds each side |
| 2 | Full side plank, feet staggered | 3 x 20 seconds each side |
| 3 | Full side plank, feet stacked | 3 x 30 seconds each side |
| 4 | Side plank with top leg raised | 3 x 15 seconds each side |
| 5 | Side plank with hip dips or reach-throughs | 3 x 8 slow reps each side |
| 6 | Feet-elevated or loaded side plank | 3 x 20 seconds each side |
Stage 1: on your knees
Bend both knees to about 90 degrees so your feet are behind you. The lever is short, so the load is lighter, but every positional demand is the same. This is where you learn to keep the hips forwards. Plenty of fit people are surprised how much this one asks of them once the form is strict.
Stages 2 and 3: the full side plank
Straighten your legs. Staggering the feet, top foot in front of the bottom one, gives you a wider base and makes balance easier. Stacking them narrows the base and asks more of the hip muscles. Do not rush from staggered to stacked: if your hips start rotating forwards to find balance, go back a step.
Stage 4: raising the top leg
Lifting the top leg a hand’s width turns this into a hard exercise for the outer hip of both legs. The bottom leg’s glute has to hold the pelvis up, the top leg’s glute has to hold the leg up. This version has real carry-over to single-leg strength and knee control, and it gets humbling quickly.
Stage 5: adding movement
Hip dips (lowering the hips a few centimetres and lifting them again) and reach-throughs (threading the top arm under your body and back up) add movement while the trunk keeps working. Go slowly. Fast reps let momentum do the job.
Stage 6: elevating the feet or adding load
Resting your feet on a bench makes the body angle steeper and the hold harder. Alternatively, keep the standard position and rest a light dumbbell on your top hip, holding it in place with your hand. Small increases go a long way here. You do not need to hold a side plank for two minutes; making a 30-second hold harder is a better use of time than making it longer. The same logic applies to front planks, which I cover in how long you should really hold a plank.
Common faults and how to fix them
- Hips sitting back. The most common fault by far. You bend at the hip and your bottom pokes out behind you. Squeeze the glutes and imagine pushing your belt buckle forwards.
- Sagging in the middle. The hips drop towards the floor. Usually a sign the version is too hard. Regress or shorten the hold.
- Shrugging into the shoulder. Your ear drifts towards your supporting shoulder. Push the floor away and make your neck long.
- Rolling forwards. The top shoulder and hip tip towards the floor. Keep the chest open and look straight ahead, not down.
- Elbow too far forwards. It feels easier but loads the shoulder awkwardly. Elbow under shoulder, every time.
- Holding the breath. If you go red, you are bracing too hard. Breathe and drop the time.
Where to put it in a session
Side planks sit well at the end of a warm-up, where a couple of easy sets switch on the hip and trunk before squats or lunges. They also fit at the end of a session alongside other core work such as the Pallof press or a suitcase carry, which train the same anti-bending and anti-rotation qualities standing up. I would not put hard side planks before heavy lifting; tired trunk muscles are not what you want under a barbell.
Train both sides equally, and start with your weaker side. If one side is clearly worse, give it an extra set rather than trying to hold it longer.
Core work counts towards the muscle-strengthening activity the NHS recommends on at least two days a week, but it should sit alongside work for the legs, back, chest, shoulders and arms rather than replace it.
Who should be careful
The side plank puts weight through one shoulder, so anyone with a shoulder injury should start with the knee version or a standing alternative and see how it feels. Check with your GP or a physiotherapist first if you have a current back or shoulder problem, are pregnant or recently postnatal, have a heart condition or high blood pressure, or are returning after a long break. Pain is a signal to stop, not something to push through.
If you would rather have someone watching your position, this is exactly the kind of thing we coach in the private studio downstairs. A 1-1 personal training session in Highgate lets me check alignment from every angle and pick the right stage for you, rather than guessing from a video. You can read more about The Highgate House on our homepage.
Questions we get asked
How long should I be able to hold a side plank?
There is no magic number. Being able to hold 30 to 45 seconds each side with clean form is a reasonable general target. Beyond that, make the version harder rather than holding longer.
Do side planks get rid of love handles?
No. Exercise strengthens the muscle underneath, but you cannot choose where your body loses fat. Overall training, food and sleep drive that.
How often should I do them?
Two or three times a week is plenty. Short, good-quality sets beat daily long holds.
Is one side being weaker a problem?
Small differences are normal. A large, persistent gap is worth working on, and worth mentioning to a coach. See our personal training page for how we assess this.
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