AdductorsBodyweightIntermediate

How to Do a Copenhagen Plank

By Bryan Alger, Co-Founder of Gravitus

· Updated Oct 1, 2026

A Copenhagen plank is a side plank with your top leg on a bench. The inner thigh of that leg holds your hips up, so it trains the hip adductors first, with the obliques helping. Start with your knee on the bench, then move to your ankle. Most people do 2 to 3 holds of 10 to 30 seconds per side.

Sets x hold 2-3 x 10-30 s per side

Muscles Adductors, obliques

Equipment A bench, box or sturdy chair

Too hard? Put your knee on the bench

Technique

How to do a Copenhagen plank

Lie on your side next to a flat bench, with your forearm on the floor and your elbow under your shoulder.
Put your top leg on the bench. Rest the inside of your knee on it for the easier short lever, or the inside of your ankle for the full long lever.
Press your top leg down into the bench and lift your hips until your head, hips and feet form one straight line.
Lift your bottom leg up to meet the bench, or let it hang just off the floor. Keep your hips stacked, not rolled forward or back.
Breathe in short, steady breaths and hold. End the set when your hips start to drop, then switch sides.

Progression

From short lever to long lever

Step 1Knee on the benchThe short lever. Your knee sits on the bench, so your thigh carries a shorter lever and your knee carries none.

Step 2Ankle on the benchThe long lever. The whole leg spans the gap, so your adductors hold more load. Move up once 30 seconds on the knee is clean.

Step 3Raise and lowerThe version the trials used. Lower your hips to the floor and lift them back up, 6 to 15 slow reps per side.

Step 4Add weightHold a plate or dumbbell on your top hip. The step to take once longer holds stop getting harder.

The further the bench is from your hip, the harder your adductors work to hold you up. Supported at the ankle, the Copenhagen exercise produced higher peak and average hip adduction torque than supported at the knee (Marušič 2026). In a modelling study of eight common adductor exercises, the long lever ranked in the top tier for every adductor muscle, and the short lever for the adductor longus and brevis (Collings 2026). Once the long lever is easy, holding longer adds little. Over 8 weeks of low-dose training, plain Copenhagen holds did not significantly raise hip adduction strength in rugby players, and weighted holds raised it 10% (O'Connor 2025).

Anatomy

Muscles worked

Adductors of the top leg (longus, brevis, magnus, gracilis)Hold your hips up against the bench, and the bottom leg's adductors work when you lift it to the bench. The long lever produced the highest forces across most adductor muscles of the eight exercises tested (Collings 2026).

Primary

ObliquesStop your waist from sagging toward the floor, as in a side plank.

Secondary

ShoulderHolds your upper body up on your forearm. Keep your elbow under your shoulder.

Stabilizer

Research

Copenhagen plank claims the research does not back

The groin injury research is real, but it did not test the plank most guides show. The trials used the Copenhagen adduction, the raise and lower version, usually with a partner holding the top leg.

Copenhagen planks cut groin injuries by 41%. That number comes from 652 male semi-professional footballers. Teams that did a program built on the raise and lower version, 3 times a week in preseason and once a week in season, reported groin problems 41% less often than teams that trained as normal (Harøy 2019). In 202 high school footballers, a program with the same exercise cut the rate of groin pain injuries by more than half (Fujisaki 2022). We found no trial that tested static Copenhagen holds for injuries.
A 2025 meta-analysis showed it does not prevent groin injuries. That review was retracted in 2026. The journal found it misrepresented the outcomes of two of the three studies it pooled for injuries (Quintana-Cepedal 2025, retraction notice).
The longer you hold, the stronger you get. In 8 weeks of low-dose training, plain holds did not significantly raise hip adduction strength, while holds with added weight did (O'Connor 2025). The raise and lower version raised eccentric adduction strength 36% in 8 weeks (Ishøi 2016).
It is mainly a core exercise. Your obliques work, but the adductors do the heavy work. In the EMG study that introduced the exercise, the Copenhagen adduction drew up to 108% of a maximal effort in the adductor longus, while abdominal and glute activity stayed relatively low across the adduction exercises tested (Serner 2014, Schaber 2021).

Compare

Copenhagen plank vs side plank vs hip adduction machine

Attribute	Copenhagen plank	Side plank	Hip adduction machine
Works most	Adductors, then obliques	Obliques, glute med	Adductors
Loaded with	Bodyweight and lever length	Bodyweight	A weight stack
Make it harder	Ankle on the bench, then reps, then weight	Raise your top leg	A heavier pin
Best for	Groin strength for running, kicking and cutting	Core endurance	Adding weight week by week

Verdict

Pick the Copenhagen plank over the side plank if your sport has sprints, kicks or quick changes of direction. The side plank trains the obliques and glute med (Ekstrom 2007), not the inner thigh. No study has compared the Copenhagen plank with the adduction machine. The machine is easier to load in small steps, and the Copenhagen exercise has the injury trial.

Programming

Sets, hold time and progression

2-3Sets per side

10-30 sHold

2-3xPer week

Do 2 to 3 holds per side, 2 to 3 times a week, at the end of a session. End each hold when your hips start to drop. Start on the short lever with 10 to 20 seconds and add 5 seconds a week.

Once you can hold the long lever for 30 seconds on both sides, switch to raise and lower reps. The trials started at 2 sets of 6 reps per side, twice a week, and built to 3 sets of 15 over 8 weeks (Ishøi 2016), or used 1 set per side 3 times a week (Harøy 2017). In season, once a week was enough to keep the injury benefit in Harøy 2019.

Form

Common mistakes

Sagging hipsYour waist drops and the adductors stop holding you up. Press the top leg into the bench and lift your hips back into line.
Hips rolling forward or backYour body twists and the load moves off the inner thigh. Stack one hip directly over the other.
Elbow out of lineAn elbow ahead of or behind your shoulder strains the shoulder. Set it directly under your shoulder.
Starting on the long leverAnkle on the bench on day one usually means a 5-second hold with sagging hips. Start with your knee on the bench.
Pushing through knee painThe long lever bends your knee sideways under load. If the inside of your knee hurts, move the bench under your knee.
Holding your breathKeep breathing in short, steady breaths while you hold the brace.

Variations

Copenhagen plank variations

Short-lever Copenhagen plankKnee on the bench instead of the ankle. The place to start.

Side PlankBoth legs on the floor. Trains the obliques and glute med, not the inner thigh.

Seated Hip AdductionThe machine version. Easy to load in small steps.

Copenhagen adduction (raise and lower)Lower your hips to the floor and lift them back up. The version used in the injury trials (Harøy 2019).

Weighted Copenhagen plankA plate or dumbbell on your top hip. Weighted holds raised hip adduction strength 10% in 8 weeks (O'Connor 2025).

PlankThe front plank. Trains the abs and shoulders, not the adductors.

FAQ

Questions people ask

Which leg is working in a Copenhagen plank?

The top leg, the one on the bench. Its adductors hold your hips up. The bottom leg's adductors work too when you lift it up to meet the bench.

How long should I hold a Copenhagen plank?

Start with 2 to 3 holds of 10 to 20 seconds per side on the short lever, knee on the bench. Add 5 seconds a week. At 30 seconds on the long lever, switch to raise and lower reps or add weight instead of holding longer.

What is a good Copenhagen plank time?

On Gravitus, as of September 2026, the median longest Copenhagen plank logged is 30 seconds for both men and women. The top 10% of men have held 45 seconds or more, and the top 10% of women 55 seconds or more (750+ men, 230+ women). Thirty clean seconds on the long lever is a solid target. Past that, make it harder rather than longer.

Why are Copenhagen planks so hard?

Your adductors hold your hips up through a long lever, a job they rarely do in daily life or in most gym lifts. The long lever produced the highest adductor forces of eight exercises in one study (Collings 2026). Move the bench under your knee to shorten the lever.

Is Copenhagen plank bad for knees?

Not usually, but the long lever, ankle on the bench, bends the knee sideways under load and can bother the inside of the knee. If it does, use the short lever with your knee on the bench, which takes the knee out of the lever.

Does the Copenhagen plank prevent groin injuries?

The raise and lower version does, in footballers. A program built on it cut the risk of groin problems by 41% in 652 male semi-professional players (Harøy 2019). We found no injury trial of static holds. A 2025 review that found no effect was retracted in 2026.

Is the Copenhagen plank better than the hip adduction machine?

For groin injury prevention, yes. The Copenhagen exercise has an injury trial, and we found none for the machine. For adding weight in small steps, the machine is easier. No study has compared the two directly, so many lifters use both.

Why is it called Copenhagen plank?

It is named after the sports medicine researchers in Copenhagen, Denmark, who introduced the Copenhagen adduction as a new exercise in a 2014 study of elite footballers (Serner 2014).

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References