Double Leg Iron Cross (How To, Benefits & Alternatives)

The Double Leg Iron Cross is a dynamic mobility exercise that focuses on rotational flexibility in the spine, hips, and core. By swinging both legs side-to-side while lying on your back, you stretch and mobilize the lower back and hip areas while also lightly activating your core to control the movement.

It’s excellent for improving flexibility, reducing tightness, and preparing the body for rotational or lower-body work.

Primary Muscles Worked: Lower Back, Obliques, Hip Rotators
Secondary Muscles Worked: Hamstrings, Core Stabilizers
Equipment Needed: None (mat optional for comfort)

How To Do Double Leg Iron Cross

Step-by-Step Instructions

Set-Up:
- Lie flat on your back with your arms extended straight out to the sides (T-shape) for stability.
- Lift both legs up so your hips and knees are at 90 degrees (knees bent or legs straight, depending on mobility).
Execution:
- Keeping your shoulders flat on the floor, slowly lower both legs to one side, twisting through the hips and spine.
- Hover just above the floor or gently tap the ground with your feet—don’t slam them down.
- Use your core to pull your legs back up to the starting position.
- Repeat the motion to the other side in a controlled, smooth manner.
Tips for Proper Form:
- Keep your arms wide and pressed into the floor for support.
- Move slowly—this is about control, not speed.
- Keep the range of motion within your limits—don’t force a deeper twist if it feels uncomfortable.

Key Benefits

Improves spinal mobility and hip flexibility.
Activates the core and rotational stabilizers.
Reduces stiffness in the lower back and hips before heavy lifting or athletic movement.

Modifications and Variations

Easier Option:
- Bend the knees more to shorten the lever and reduce strain.
Harder Option:
- Keep legs fully straight during the swing.
- Slow the movement down and add a pause at the bottom for more core control.

Common Mistakes

Letting the Shoulders Lift Off the Floor: Keep them anchored down to isolate the twist at the hips and spine.
Rushing the Movement: Move with control to prevent lower back strain.
Dropping Legs Too Hard: Always control the descent to protect the spine.

Reps and Sets Recommendations

For Warm-Up or Mobility Work: 2–3 sets of 8–10 reps per side, moving slowly and deliberately.
For Core Control Practice: 2–3 sets of 6–8 very slow, high-control reps per side.
As a Cooldown: 1–2 sets of 10–12 reps per side with a focus on stretching, not speed.

Double Leg Iron Cross Alternatives

Reach Thru and Rotate

Reach Thru and Rotate is one of my favorite exercises for working on improving mobility through the Thoracic and Lumbar Spine (mid and low-back).

Start on all fours (hands and knees). Brace on one hand and take the other arm and reach it through the gap between the braced arm and the leg. Hold that stretch for a moment and then rotate and open as far as possible, taking the eyes and fingertips straight up to the sky.

Repeat back and forth and then switch to the other side.

Bodyweight Good Mornings

Bodyweight Good Mornings do not have the same rotational stretch the Double Leg Iron Crosses have, but they are a great dynamic low back and glute warm-up in their own right.