A Copenhagen plank is a side plank where your top leg rests on a bench and your inner-thigh muscles hold your hips up. To start safely, lie on your side next to a bench, place your top knee on it, put your elbow under your shoulder, and lift your hips until your body is straight. Hold for 10 to 20 seconds. Once that’s easy, move the bench contact to your ankle for the full version, which is much harder.
Why it matters for men over 40
The adductors, the muscles along the inner thigh, get little direct work in most gym programs. They matter in any sport with sprinting, cutting or kicking: hockey, soccer, basketball, tennis. Weak adductors are a common factor in groin strains, which take a long time to settle in older athletes.
There’s good evidence that this exercise helps in sport. In a cluster-randomised trial of 652 semi-professional male football players in Norway, teams that used an adductor program based on the Copenhagen exercise had a 41% lower risk of reporting groin problems during the season (Harøy et al., 2019). Those were younger footballers, but the principle holds for a man in his forties who still plays.
Setup
- Place a flat bench next to a mat.
- Lie on your side, perpendicular to the bench, with your top leg on the bench.
- Short lever: the bench is under your top knee.
- Long lever: the bench is under your top ankle.
- Your bottom leg hangs under the bench. Elbow directly under your shoulder.
How to perform it
- Press your top leg down into the bench.
- Push through your elbow to lift your shoulder away from your ear.
- Lift your hips until your body forms a straight line from head to top foot.
- Let your bottom leg hang, or lift it up to touch the underside of the bench for a harder version.
- Hold, breathing steadily.
- Lower your hips with control. Switch sides.
Mistakes to avoid
Starting with the long lever. Too much load on the groin too soon. Spend several weeks in the knee version first.
Hips dropping. You’re past your limit. End the hold.
Rolling forward. Keep hips stacked, top hip over bottom hip.
Training it every day at first. The adductors get sore quickly. Two or three times a week is enough.
Holds and progressions
| Level | Version | Sets × hold per side | Frequency |
|---|---|---|---|
| Starting | Short lever (knee on bench) | 2–3 × 10–15 s | 2 × a week |
| Building | Short lever | 3 × 20–30 s | 2–3 × a week |
| Advanced | Long lever (ankle on bench) | 3 × 10–20 s | 2 × a week |
| Dynamic | Long lever with bottom leg raises | 3 × 6–8 reps | 1–2 × a week |
Easier, harder and joint-friendly options
- Easier: a regular side plank, side-lying adductor raises, or squeezing a ball between your knees while lying down.
- Harder: long lever, adding reps of the bottom leg lifting to the bench, or holding a light weight on the top hip.
- Sore knees: stay with the knee on the bench, with a towel underneath for padding.
- Sore shoulder: do the version with your hand on the floor under your shoulder, or reduce the hold time.
- Groin pain: stop. Get it assessed by a physiotherapist before loading it again.
Split squats and the single-leg RDL round out the hip work for players returning to sport.
Workouts that use it
The Copenhagen plank is part of the core workout and the knee friendly leg workout. For a full program that fits groin and hip work alongside strength days, see the DIY programs.
Questions people also ask
What does the Copenhagen plank work?
Mainly the adductors, the inner-thigh muscles of the top leg, along with the obliques and the hip muscles of the bottom leg.
Is the Copenhagen plank hard?
The full version with the ankle on the bench is very hard. Start with the knee on the bench, which shortens the lever, and progress gradually.
Can the Copenhagen plank prevent groin injuries?
In a trial with semi-professional male football players, a program built on the Copenhagen adduction exercise reduced groin problems over a season. That was in footballers, not recreational lifters, but it shows the exercise is useful for anyone in a sport with cutting and kicking.
My inner thigh is sore after Copenhagen planks. Is that normal?
Some muscle soreness is normal when you start, especially the next day. Sharp pain in the groin during the exercise isn't; stop and get it assessed.