Bent-Knee Lying Twist

Body Part: Core

Muscle: Abs

Equipment: Body Weight

The Bent-Knee Lying Twist is a floor-based rotational core exercise where the knees move side to side while the upper body stays anchored. Bending the knees shortens the lever compared with straight-leg twists, making it easier to control the obliques, abs, hip flexors, and lower back.

This exercise is useful for building gentle rotational control and learning how to move the pelvis and legs without losing shoulder contact with the floor. The goal is not to force the knees all the way down, but to rotate only as far as the core can bring them back smoothly.

Set up on your back with the knees bent and lifted, arms out to the sides, and shoulders relaxed into the floor. Lower both knees toward one side, pause before the opposite shoulder lifts, and return to center with control before moving to the other side. The lower back should feel supported, not strained.

Use Bent-Knee Lying Twists as a warmup, cooldown, mobility drill, or light core accessory. Slow breathing and controlled range make the movement more productive than speed. If your lower back feels uncomfortable, keep the feet closer to the floor or reduce how far the knees travel.

Instructions

• Lie on your back with your knees bent and lifted over your hips.
• Extend your arms out to the sides with palms on the floor for light support.
• Brace gently and keep both shoulders relaxed against the floor.
• Slowly lower both knees toward one side as a unit.
• Stop before the opposite shoulder lifts or the lower back feels strained.
• Use your obliques to bring the knees back to the center.
• Lower the knees toward the other side with the same control.
• Continue alternating sides while breathing steadily.

Tips & Tricks

• Move slowly enough that the knees do not drop under gravity.
• Keep the arms relaxed; pressing too hard can hide poor core control.
• Limit the range if your shoulders lift from the floor.
• Keep the knees together so both sides of the pelvis rotate evenly.
• Exhale as you bring the knees back to center.
• Keep the neck relaxed and gaze upward rather than turning the head forcefully.
• Bring the feet closer to the floor if holding the legs up is too demanding.
• Use this as a control drill, not a fast ab exercise.

Frequently Asked Questions

What muscles does the Bent-Knee Lying Twist work?

It mainly works the obliques, with support from the abs, hip flexors, and lower back.

Is Bent-Knee Lying Twist beginner friendly?

Yes. The bent-knee position makes the twist easier to control than a straight-leg version.

Should my shoulders stay down?

Try to keep them down, but reduce the range if they lift or the lower back feels strained.

How far should my knees go?

Only as far as you can control while keeping the opposite shoulder close to the floor.

Should my feet touch the floor between reps?

They can if you need an easier version. Keeping the knees lifted makes the core work harder.

Why use bent knees instead of straight legs?

Bent knees shorten the lever, making the twist easier to control and often friendlier for the lower back.

What if my lower back feels tight?

Reduce the range, slow down, and keep the brace gentle. Stop if discomfort persists.

Can this be used as a warmup?

Yes. Slow bent-knee twists work well before training that needs trunk rotation or hip mobility.