Most people scroll past the plank. It’s the exercise everyone half-commits to while eyeing the clock, waiting for the thirty-second mark to arrive so they can stand back up. Fair enough – a basic plank rarely earns much respect. But hear me out, there’s a version of this exercise that flips the script entirely, and it’s brutal enough that nobody finishes it bored.
It’s called the Copenhagen plank, and it’s gotten its name from the Danish soccer club that built it into their training program years ago. Once physical therapists and strength coaches noticed how effective it was at protecting athletes from groin injuries, it spread well beyond the pitch. Today it shows up in the routines of runners, sprinters, and anyone tired of core work that stops delivering results.
Here’s the deal, though: you will not be timing this one in minutes. If you’re doing it with proper form, you’ll be fighting to hold the position for even twenty or thirty seconds. That’s the whole point.
What Makes It So Different From a Regular Plank
A standard side plank is mostly a bracing exercise. You lock your core down and hold your body in a straight line, and your obliques do the bulk of the work. The Copenhagen plank keeps that demand but stacks a second one on top of it.
Related: The Truth About Planks: Benefits, Risks, and How Long You Should Actually Hold One
Because your top leg rests on an elevated surface while your bottom leg hangs free in the air, your inner and outer thigh muscles – the adductors and abductors – have to kick in hard just to keep your hips from dropping. That’s real estate most core exercises never touch. Add in the fact that your whole body is essentially unsupported on one side, and your core has to work overtime just to stop you from twisting or folding forward.
The position also happens to mirror the stride of a runner mid-sprint, which is a big reason this move earned a permanent spot in so many athletes’ warm-ups. Holding that shape under tension trains the same stability you rely on every time one foot leaves the ground.
The Benefits Go Beyond a Stronger Core
It protects your hips. The adductors are muscles most training programs completely ignore, which is part of why groin strains are so common in sports involving sudden direction changes. One study following dozens of semi-professional soccer teams found that squads who added this exercise into their preseason and in-season routines saw noticeably fewer groin injuries than teams who skipped it. Strengthening a muscle group that rarely gets direct attention tends to pay off exactly where you’d expect.
It strengthens your shoulders too. Because your entire upper body weight rests on one supporting arm, your shoulder stabilizers – the muscles around your shoulder blade and rotator cuff – end up working far harder than they would in almost any other core drill. Stronger stabilizers here mean a more resilient shoulder joint over time. Related: 8 Tips for Bigger, Healthier Shoulders
It builds anti-rotation strength. Your free leg stays lifted and bent through the whole hold, which forces your core to resist rotating or sagging in either direction. That kind of control transfers directly to sports, lifting, and honestly just picking things up off the floor without tweaking your back.
It improves balance and lateral stability. Because you’re supporting your entire body asymmetrically, your core and hips have to coordinate in a way that two-footed planks never demand. That carries over to anything involving quick side-to-side movement – cutting on a field, dodging on a court, or catching yourself on uneven ground.
How to Do the Copenhagen Plank
You’ll need a bench, box, or any sturdy elevated surface without a backrest in the way.
- Set up your top leg on the bench. Lie on your side and rest the top of your foot or shin on the bench. Starting with your knee closer to the bench makes the move easier; sliding your foot further out lengthens the lever and ramps up the difficulty fast. If this is your first attempt, start with just a couple of inches of separation.
- Drop into a side plank. Prop yourself up on your forearm, keeping your elbow stacked directly under your shoulder. Squeeze your shoulder blade down and back, and brace like you’re about to get punched in the stomach.
- Lift your hips until your body forms a straight line. Push through the top foot to raise your hips off the floor. Your bottom leg should hover a few inches below the top one – not resting on the ground, not flailing for balance.
- Hold, and fight to stay square. Keep your gaze forward, glutes squeezed, and resist any urge to let your hips sag or your torso creep forward. Start with 15 to 30 seconds per side, or a handful of controlled reps raising and lowering your hips, and build from there.
Since this move demands so much from a fresh core and fresh shoulders, it’s worth doing first in your workout – before fatigue makes good positioning impossible.
Mistakes That Quietly Wreck the Exercise
Letting your hips sag. If your hips dip toward the floor, your adductors and core aren’t yet strong enough to hold the position at that range. The fix isn’t to power through – it’s to slide more of your leg onto the bench, shortening the lever until your form holds up.
Letting your torso drift forward. This usually means your shoulder and core endurance hasn’t caught up yet. Rather than fighting through bad positioning, drop back to a standard side plank for a few weeks and build a foundation before trying the Copenhagen version again.
Rushing the progression. This is an advanced move for a reason. If you have a history of shoulder or knee issues, check with a doctor or physical therapist before loading up this position, since it asks a lot of both joints.
An Easier Way In
Not ready for the full version? Bend your top knee and rest it on the bench instead of your foot. This shortens the distance your body has to support, taking a significant amount of load off the position while still training the same muscles. As your strength builds, slowly walk your leg further out – first to the shin, eventually to just the ankle and foot – until you’re ready for the complete movement.
The Bottom Line
A strong core isn’t just about how your midsection looks – it’s the thing holding your whole body together every time you run, lift, twist, or catch yourself off balance. The Copenhagen plank asks more of that system than almost any other core exercise out there, hitting your hips and shoulders right along with your abs. It’s not comfortable, and it’s definitely not something you’ll knock out without focus. But if you’re willing to put in the work on form first, it might be the single most useful plank variation you’re not doing yet.
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