If your inner thigh workouts consist mostly of awkward cable machines and the occasional sumo squat, it might be time to meet the Copenhagen plank. According to Lifehacker, this underrated side plank variation is one of the most effective ways to target your adductors - the muscles that run along the inside of your thighs - and it's probably not in your routine yet.
So what exactly is it?
The Copenhagen plank is a side plank with a twist. Instead of simply propping yourself up on one forearm with your feet stacked or staggered on the floor, you elevate your top leg onto a bench or box and use it to support much of your bodyweight. Your bottom leg either hovers in the air or lightly touches the ground, depending on your version of the exercise.
That small adjustment completely changes what's being asked of your body. Your inner thighs suddenly have to work hard to keep your hips lifted and stable, rather than just sitting along for the ride the way they tend to do in a standard plank.
Why your adductors actually matter
Here's the thing about inner thigh muscles - most people only think about them aesthetically, but they play a genuinely important role in how your whole lower body moves and stays stable. Strong adductors support your hips, help protect your knees, and contribute to better performance in everything from running to squatting. Neglecting them can create muscular imbalances that eventually show up as pain or injury.
The Copenhagen plank targets this area in a way that most exercises simply don't. It's a functional, challenging movement that builds real strength rather than just going through the motions.
How to get started
The beauty of this exercise is that it scales well. If you're new to it, start with your bottom knee on the ground and your top leg resting on a low bench. Hold for 10-20 seconds, rest, and repeat. As you get stronger, you can progress to lifting that bottom leg off the floor entirely, turning it into a full Copenhagen plank.
Keep your hips stacked and your core tight throughout - the temptation to let your hips drop or rotate forward is real, and giving in to it defeats the purpose. A few sets on each side is plenty to start, especially since your adductors may be far less conditioned than you expect.
The takeaway
The Copenhagen plank is one of those exercises that looks deceptively simple until you actually try it. If you've been overlooking your inner thighs in your training - and most of us have - this is a smart, efficient way to fix that without needing a lot of equipment or extra gym time.
