Copenhagen Plank

Hold a side-plank position with your top leg supported and press that leg into the support to load the inner thigh (hip adductors) while the core stabilizes the hips. Maintain a straight line through the body throughout the hold.

How to do the Copenhagen Plank#

1. Lie on your side and set your top leg so the inner thigh rests on a stable, raised surface; align your shoulders and hips.
2. Push your top leg into the support and lift your hips until your body forms a straight line from shoulders to feet.
3. Keep your core braced and your shoulders stacked over your base while maintaining pressure through the supported leg.
4. Breathe evenly and hold the position for the chosen duration without letting the hips drop.
5. Lower your hips under control and switch sides when ready.

Muscles worked#

The Copenhagen plank is the best bodyweight exercise for the adductors, the inner thigh muscles that pull the legs together. With the top leg resting on a bench and the bottom leg hanging free, the adductors of the top leg hold your whole body up by squeezing down into the bench, and the adductors of the bottom leg lift it toward the top one. Adductor longus, the muscle most often strained in sprinting and kicking sports, takes most of the load.

The obliques on the bottom side hold the trunk straight against gravity exactly as in a side plank, so this is also a hard lateral core exercise. The abs and glutes keep the hips from rolling forward or back, and the hip abductors of the bottom leg fire to keep it lifted. The inner thigh is the first thing to shake and usually the first thing to fail.

Common mistakes#

• Allowing the hips to sag instead of holding them level.
• Rotating the torso forward or backward instead of keeping shoulders stacked.
• Letting the supported leg slip forward or backward off the support.
• Holding your breath during the hold.

Why it works#

The adductors are the most neglected muscles in most lifters' legs. Squats and lunges use them, but never hard enough to stop them being the weak link in a sprint, a change of direction, or a deep squat. The Copenhagen plank loads them harder than any machine, with nothing but a bench, in a long position the hip adduction machine cannot reach.

It also has some of the strongest injury-prevention evidence of any single exercise. A large randomised trial of a Copenhagen adduction programme in male footballers cut groin problems by roughly 40 percent across a season with a few minutes a week. Anyone who plays a field sport or has a history of groin tightness should treat two short sessions a week as non-negotiable.

Sets, reps and setup#

Two to three sets per side of 15-30 second holds, twice a week, with 60 seconds of rest. Start with the short lever version, knee on the bench, and hold as long as the hips stay level. The full version with the ankle on the bench is much harder; most people need several weeks to earn 30 seconds there.

Setup

Lie on your side with the top leg on a flat bench, knee for the easier version or lower shin and ankle for the harder one. Forearm on the floor under the shoulder, bottom leg beneath the bench. Squeeze the top leg down into the bench and lift the hips and bottom leg until you are one straight line from head to heel. Do not let the hips drop or the torso roll.

Progression

Move from knee to mid shin to ankle as holds pass 30 seconds. Then add slow reps: lower the hips toward the floor and lift back up for 6-10 repetitions, or lift and lower the bottom leg while holding the plank. Only then is it worth adding weight.

Variations#

• Side Plank Feet on the floor, so the obliques do the work and the adductors are barely involved.
• Star Side Plank Top leg lifted into the air, loading the abductors of the top leg rather than the adductors.
• Machine Hip Adduction Seated and isolated, heavier loads and more reps but a shorter, less athletic range.
• Cossack Squat Dynamic adductor work through a deep lateral squat, a good pairing on the same day.

Copenhagen plank vs side plank#

The side plank puts both feet on the floor and asks the obliques and the bottom hip to hold the trunk up. It is a core exercise that also works the outer hip. The Copenhagen plank lifts the top leg onto a bench and pulls the bottom leg off the floor, so the inner thigh of the top leg becomes the thing holding you up.

For a lateral core exercise, either works, and the side plank is easier to progress. For the adductors, the side plank does almost nothing and the Copenhagen plank is the exercise. Athletes in sprinting and kicking sports should treat it as a hamstring curl for the groin.