The Copenhagen Plank is an advanced modification of the traditional side plank that specifically targets the adductor muscles of the inner thigh, alongside the core stabilizers. Developed for injury prevention, particularly among soccer players in Copenhagen, this exercise is highly effective for building strength in often-neglected muscle groups. It demands significant stability and strength, making it a challenging but rewarding addition to a training routine.
Targeted Muscle Groups and Functional Purpose
The primary focus of the Copenhagen Plank is the adductor muscle complex. These muscles are responsible for drawing the leg toward the midline of the body (adduction) and are crucial for maintaining hip and pelvic stability during dynamic movements. Weak adductors are strongly correlated with an increased risk of groin strain, especially in sports involving rapid cutting, pivoting, and kicking actions.
The adductor muscle complex includes:
- Adductor longus
- Adductor brevis
- Adductor magnus
- Pectineus
- Gracilis
Strengthening the adductors eccentrically significantly reduces the incidence of groin injuries in athletes. The exercise also heavily engages the core musculature, particularly the obliques and transverse abdominis, to resist rotational forces and maintain a straight body line. This dual activation of the adductors and lateral core stabilizers makes the Copenhagen Plank uniquely beneficial for improving lateral stability and overall athletic performance.
Step-by-Step Execution of the Standard Plank
To begin the standard version, use a sturdy elevated surface, such as a bench or box, that is roughly knee-height. Lie on your side, perpendicular to the bench, positioning your bottom elbow directly beneath your shoulder on the floor. The top leg (the working leg) should be placed entirely on the bench, with the inner ankle or foot resting securely on the surface.
The bottom leg remains straight and suspended underneath the bench. Brace your core and glutes, then push down into your forearm and the elevated top leg to lift your hips off the floor. The goal is to create a perfectly straight line from your head, through your hips, and down to your heels, avoiding any sagging or arching in the lower back.
The adductor contraction on the top leg drives the body upward and maintains the hold while the bottom leg hovers freely. Maintain slow, controlled breathing, concentrating on keeping the hips elevated and square. Hold this position for the desired duration, typically 10 to 30 seconds, before lowering the body with control and repeating on the opposite side.
Scaling the Movement for Different Ability Levels
The difficulty is determined by the length of the lever created by the top leg on the elevated surface. For beginners, the most common regression is the short-lever variation, where the top leg is bent at a 90-degree angle and the knee and shin rest on the bench. This modification significantly reduces the force required from the adductors, allowing individuals to build foundational strength.
To increase the challenge, progressively lengthen the lever by moving the contact point further away from the hip. This transitions the support from the knee/shin to the inner calf, and finally to the inner ankle or foot (the full-lever, standard version). Once the static hold can be maintained for over 30 seconds with excellent form, dynamic variations can be introduced, such as performing slow, controlled hip dips or incorporating a knee drive by lifting the bottom leg.
Common Errors and Injury Prevention
A frequent mistake is allowing the hips to sag toward the floor, which shifts tension away from the adductors and core, placing undue stress on the lower back. To correct this, actively squeeze the glutes and tuck the pelvis slightly forward to maintain a rigid, straight line from head to heel.
Another common error is rotating the torso or shoulders, which indicates a loss of stability in the obliques. The body must remain perpendicular to the floor, and you should ensure the shoulder of the supporting arm does not shrug up toward the ear. Neck strain can occur if the head is hyperextended, so keep your gaze directed straight ahead or slightly down to maintain a neutral spine alignment.
Individuals experiencing acute groin pain or a recent adductor strain should avoid this exercise until cleared by a medical professional, as the high tension can aggravate the injury. Stop the exercise immediately if you cannot maintain proper form, as continuing with poor technique increases the risk of injury.