Double-Under

A double-under is a jump-rope exercise where the rope passes under your feet twice in one jump. It trains your calves to produce quick, springy jumps and also works your shoulders, forearms, and core as they turn the rope and keep your body stable.

Start with your feet under your hips, knees soft, and your weight on the balls of your feet. Hold the rope handles lightly near your hips with your elbows tucked in and your wrists ready to spin. Stand tall, eyes forward, and relax your shoulders.

Jump with a small, consistent bounce. Do not bend your knees deeply or kick your feet back. As you leave the ground, spin the rope fast with quick wrist flicks while your arms stay in at your sides. Land softly and bounce again right away, keeping your posture tall and your eyes looking forward.

Breathe naturally in rhythm with your jumps and keep your midsection lightly braced so your body does not rock. If double-unders feel too much for your calves or Achilles, scale to single-unders and build your volume gradually. To make them harder, add them into intervals or string more reps together without stopping.

Fault: You swing your whole arms in big circles instead of spinning the rope with your wrists. Fix: Keep your elbows close to your ribs and make small, quick flicks with your wrists; your arms should stay in at your sides.

Fault: You do high, pogo-stick jumps to buy time for the rope to pass twice. Fix: Stay low with a small consistent bounce, barely leaving the ground; let the rope speed come from your wrists, not your jump height.

Fault: Your shoulders creep up toward your ears or you start to hunch forward. Fix: Reset to tall posture with your eyes forward and your shoulders relaxed; brace your core gently so your torso stays upright.