The Copenhagen Plank Is the One Move You Need for Stronger Abs and Thighs

With our busy day-to-day schedules, it makes sense to want to add exercises into your workout session that give you the most bang for your buck. So, if you're looking for a challenging exercise that builds both core and lower-body strength at the same time, the Copenhagen plank — a type of side plank — definitely fits the bill.

Ready to get started? Below, we'll share how to properly do this exercise, its benefits, how to make it easier or harder and the best ways to build it into your exercise routine.

• ‌What is the Copenhagen plank?‌ The Copenhagen plank is a side plank variation where one leg is supported on a bench and the other leg hovers underneath the bench and off the floor.
• ‌What is the Copenhagen plank good for?‌ You can use this exercise to build strength in your inner thigh and core muscles. Strengthening the inner thigh muscles is especially helpful in reducing your risk of groin injuries. And strong core muscles help you initiate and stabilize movements like walking, running, bending and lifting.
• ‌Copenhagen plank muscles worked:‌ The main muscles involved in the Copenhagen side plank are your adductors on the insides of your thighs and your obliques on the outside of your torso. Your shoulders and a few other core and hip muscles — including your abdominals and glutes — play a supporting role in the exercise.
• ‌Who can do the Copenhagen plank?‌ The Copenhagen plank is an advanced exercise and should not be attempted by those who haven't already built strength with standard side planks. Additionally, it's important to talk with your doctor or physical therapist before trying this exercise if you're recovering from a lower-body injury.

The adductors are a group of muscles on the insides of your thighs that are responsible for pulling your leg in toward the middle of your body. They also help stabilize your pelvis while you move. These muscles play an essential role in many popular exercises like squats and lunges, as well as athletic moves like running, cutting and kicking. Yet people often neglect strengthening them in favor of focusing on other lower-body muscles like the quads and glutes.

Strengthening your adductors can make you stronger in the weight room and improve sports performance. It also helps you get stronger in the frontal plane of your body, which means you'll have an easier time moving side to side.

Your core muscles — especially your obliques — help maintain the position of your pelvis and torso when you move. They're especially active to prevent lateral flexion, which is the sideways bending of your spine. This type of core strength and stability can protect your back and improve your performance in a variety of movements in and out of the gym.

Groin strains and injuries are very common among athletes, especially those who play sports that involve running, kicking or changing directions. Research suggests that building adductor strength with Copenhagen planks can reduce the risk of these types of injuries.

A small June 2022 study in the ‌International Journal of Environmental Research and Public Health‌ found that an eight-week exercise protocol focused on a Copenhagen plank variation reduced the risk of groin injuries in active young men. The authors of this study theorized that an increase in adductor muscle thickness combined with more muscle flexibility caused the reduction in injuries.

And, a small February 2019 study in the ‌British Journal of Sports Medicine‌ found that male soccer players who did the Copenhagen plank regularly reported significantly fewer groin injuries over the course of their season than their peers who didn't do the exercise.

While more research with wider variety of people needs to be done, if you're an athlete who wants to stay healthy and avoid a potentially season-ending groin injury, including Copenhagen planks in your workouts may help.

It's important to keep your entire body facing straight ahead when performing Copenhagen planks. Don't let your shoulders or hips rotate forward or backward. Focus on keeping your posture square and your shoulders stacked directly on top of each other.

Too much rotation is a sign that you need to build more core strength before attempting Copenhagen planks. Try doing one of the easier variations below, and if that doesn't fix the problem, spend more time working on side planks with both legs on the ground.

Another common Copenhagen plank mistake is letting your hips drop or sag. You should maintain a straight line from your top shoulders through your hips and down to your top foot.

If you let your hips drop toward the floor, you'll miss out on many of the core-strengthening benefits of this exercise. You might also experience pain in your low back or on the insides of your knees.

To fix this mistake, actively drive your hips up away from the floor. If you're still struggling, use one of the easier variations below or take a step back and get stronger with standard side planks and other adductor exercises.

A final mistake to watch out for is too much flexion in your hips. This happens when you stick your hips back behind you or when you set up your bottom arm too far in front of your legs. A proper Copenhagen plank requires full hip extension, which means your hips stay in line with your shoulders.

Sometimes this is an easy fix and you just need to set up your bottom elbow in line with your legs. Other times it's a sign that you're not yet strong enough for full Copenhagen planks and should use a regression or another exercise.

It can be tough to jump into full Copenhagen planks right away. Thankfully, you can make the exercise easier by changing your body position to make it easier on your muscles and joints.

There are several ways to do a bent-knee Copenhagen plank. The easiest option is to bend both of your knees. Another option is to only bend one knee — either your top or bottom leg.

Both options work by reducing the lever arm of the exercise, which means your muscles don't have to support as much of your body weight. These options are also helpful for people who experience knee pain when attempting full Copenhagen planks. Choose the variation that feels best on your joints and matches your current strength level.

Placing your foot on the ground reduces some of the demands on your adductors. It's a great way to get comfortable in the Copenhagen plank position before progressing to the full version.

You can add resistance to your Copenhagen planks by holding a weight in your top hand. Use a dumbbell or kettlebell so you can get a good grip on the weight. For an added stability challenge, hold a kettlebell in the bottoms-up position where you balance the round part of the bell above your hand.

Just about every plank variation can be made harder by adding movement, and the Copenhagen plank is no exception. Moving your bottom knee forces your stabilizing muscles to work harder to maintain your body position.

You can perform this Copenhagen plank progression on the floor. This variation might feel better for folks with cranky knees who struggle to support their top leg on a bench. It's also ideal for people who don't have access to a bench. But don't be fooled — this variation can be even harder than the standard Copenhagen plank.

The Copenhagen plank is a deceptively challenging exercise, and it's best to ease into it to avoid feeling frustrated or aggravating your joints.

We suggest working your way up to at least a 30-second side plank with straight legs on each side before attempting Copenhagen planks. You might also want to strengthen your adductors using exercise machines, resistance bands or other isolation exercises.

Start your Copenhagen plank journey using one of the easier variations shared above. Find one that feels good on your joints and allows you to maintain good form. Work your way up to at least 20 seconds per side before attempting full Copenhagen planks with both legs straight and your bottom leg off the floor.

Because this exercise is so challenging, it's best to perform it earlier in the workout when your muscles are fresh. Include it as part of your warmup or do your core training before your main strength movements for the day.