ProgreviaSide plank: proper form, muscles worked and common mistakes
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How to do it
Support on the forearm and the side of the foot forming a straight line from ankles to shoulders. Lift the hips and brace the bottom-side oblique without letting the hip sag; keep breathing.
Muscles worked
Main muscle: abs. When it plans weekly volume, every set of this exercise counts in full for abs: the generator does not split it with other muscles.
Side plank versus front plank: the flank tells a different story
Where the front plank spreads the effort between the front of the trunk and the shoulders, the side plank puts nearly all of it on one flank: the obliques, quadratus lumborum and gluteus medius of the underneath side work to stop the hip from dropping. This is pure lateral stability, something the Plank barely asks for and something the Pallof press trains another way, by resisting rotation. It is also a revealing exercise: if one side is clearly harder than the other, you will notice right away.
Use it to round out your core work, especially if you squat, deadlift or run and want a stable lower back against side-to-side tilting. Begin with the weaker side and match the time on the other. Bent knees make a good stepping stone, and staggering your feet, one in front of the other, gives you a wider base.
Progress with the top leg raised, the free hand reaching toward the ceiling, or gentle hip dips up and down. If your supporting shoulder feels loaded, stack the elbow right under it and push the floor away with the forearm.
Technical sheet
- Movement pattern
- Core
- Minimum level
- Beginner
- Technical demand
- Basic
- Fatigue it generates
- Low (0.4 out of 2.2)
- Risk if technique breaks down
- Low
These are the values the generator uses to decide where the exercise goes within the session.
Recommended sets and reps
As an isometric exercise, it is programmed by time: 3–4 sets of 20–45 seconds holding tension without losing position. Increase time under tension before adding difficulty.
Common mistakes to avoid
- Letting your hips drop toward the floor: once they sag, the obliques stop holding you up.
- Sticking with the same version once you can hold it for more than a minute: move to a harder variation.
- Holding longer than you can keep your position: the moment your form breaks, the set is over.
What the research says
As an isolation move, it is mostly a way to add volume to one muscle. Gentil and colleagues (2013) found that, in beginners, adding it to a multi-joint exercise gave no extra arm growth; it pays off later on, or for muscles the compounds barely reach.
You do not need to reach failure on every set: according to the meta-analysis by Refalo and colleagues (2023), stopping one or two reps short gives very similar growth. The generator prescribes it with RIR for that reason.
- Gentil P, Soares SR, Pereira MC, et al. Effect of adding single-joint exercises to a multi-joint exercise resistance-training program on strength and hypertrophy in untrained subjects. Applied Physiology, Nutrition, and Metabolism. 2013;38(3):341-344.
- Refalo MC, Helms ER, Trexler ET, Hamilton DL, Fyfe JJ. Influence of resistance training proximity-to-failure on skeletal muscle hypertrophy: a systematic review with meta-analysis. Sports Medicine. 2023;53(3):649-665.
How Side plank compares with other abs exercises
Of the 14 abs exercises in the catalogue, ranked from least to most fatiguing by the values the generator uses, Side plank is number 3 (tied with 4 others).
That makes it a good candidate for adding abs sets at the end of a session or in heavy weeks, when you want volume without extra fatigue.
With different equipment, the same movement pattern offers 3 alternatives, such as Cable crunch, Pallof press and Landmine rotation.
| Exercise | Equipment | Fatigue | Technique |
|---|---|---|---|
| Bicycle crunch | bodyweight | Low (0.4 out of 2.2) | Basic |
| Cable crunch | cable | Low (0.4 out of 2.2) | Basic |
| Pallof press | cable | Low (0.4 out of 2.2) | Needs coaching |
| Plank | bodyweight | Low (0.4 out of 2.2) | Basic |
| Side plank | bodyweight | Low (0.4 out of 2.2) | Basic |
| Hollow hold | bodyweight | Low (0.5 out of 2.2) | Needs coaching |
| Lateral plank walk | bodyweight | Low (0.5 out of 2.2) | Needs coaching |
| Hanging leg raise | bodyweight | Low (0.6 out of 2.2) | Needs coaching |
Bodyweight. In the trial by Kotarsky et al. (2018), four weeks of progressively harder push-ups significantly improved bench press 1RM, just like training the bench press itself. It is a strength result, not a hypertrophy one, and the condition is the word progressive: the exercise has to keep getting harder.
An isolation exercise. In the trial by Gentil et al. (2015), with untrained young men over ten weeks, the biceps curl and the lat pulldown were equally effective for gaining strength and size in the elbow flexors: isolation is not filler.
- Kotarsky CJ, Christensen BK, Miller JS, Hackney KJ. Effect of progressive calisthenic push-up training on muscle strength and thickness. Journal of Strength and Conditioning Research. 2018;32(3):651-659.
- Gentil P, Soares S, Bottaro M. Single vs. multi-joint resistance exercises: effects on muscle strength and hypertrophy. Asian Journal of Sports Medicine. 2015;6(2):e24057.
Related guide
How Long to Hold a Plank: Technique and Variations
Alternative exercises
More core exercises
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Frequently asked questions
What muscles does Side plank work?
Side plank mainly works the abs muscle group, plus synergist and stabilizer muscles depending on the variation.
How many sets of Side plank should I do?
Between 3 and 4 sets of 20–45 seconds per session. With isometrics you progress by extending time under tension or adding difficulty (weight, less stable support), not by counting reps.
Is it normal for one side to be harder in the side plank?
Yes, it is very common: hardly anyone is symmetrical. Start with the weaker side, let it set the time, and match that on the other side instead of holding longer on the strong one. The gap usually narrows over a few weeks. If it is large or pain shows up, it is worth having it checked.
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