Waist Exercise · Body Weight

Lying Elbow To Knee form demonstration - targeted for Abs Waist workouts

Lying Elbow To Knee

Bringing the elbow to the opposite knee while lying down trains rotation and hip flexion together, similar to a bicycle crunch but performed at a slower, more controlled pace. The slower tempo is what makes it worth doing — rushing through turns it into momentum instead of muscle work.

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Category
Waist
Equipment
Body Weight
Target
Abs

Exercise reference published by PlanWorkouts; see our editorial standards.

How to Do the Lying Elbow To Knee

  1. Lie flat on your back with your knees bent and feet flat on the ground.
  2. Place your hands behind your head with your elbows pointing outward.
  3. Engage your abs and lift your upper body off the ground, bringing your right elbow toward your left knee.
  4. At the same time, extend your right leg straight out and lift it off the ground.
  5. Pause briefly, then return to the starting position.
  6. Repeat the movement, this time bringing your left elbow toward your right knee and extending your left leg.
  7. Continue alternating sides for the desired number of repetitions.

Quick Exercise Facts

Movement Type Targeted (Isolation)
Equipment Body Weight
Main Muscle Abs
Supporting Muscles Lower Back

Target Muscle Activation

Abs — Main Target
Hip Flexors — Supporting
Stabilizers — Balance & Core

Recommended Sets & Reps by Goal

Build Muscle & Size 3 – 4 Sets × 10 – 15 Reps

Moderate weight · 60s rest

Tone & Shape 3 Sets × 15 – 25 Reps

Lighter weight · 30–45s rest

Form & Control 2 – 3 Sets × 12 – 15 Reps

Lower slowly for 3 seconds · 60s rest

Technique & Form Tips

Focus on trunk flexion, rotation, or anti-movement stability as required by your specific variation. Maintain the suggested pelvic and spinal orientation to keep tension focused on the abdominal area throughout each repetition or hold.

Common Mistakes to Avoid

  • Pulling the neck: For crunch variations, avoid pulling the head forward with your hands; follow the demonstrated arm and head position.
  • Lower back arching: Keep the spine controlled to prevent the lower back from hyperextending under the load.
  • Excessive speed: Perform movements with deliberate control rather than relying on rapid, bouncing motions.

How to Breathe During This Exercise

Maintain a steady breathing rhythm during the effort.

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Comfort and Control

Choose a load and range you can control. Stop if the movement causes pain. If discomfort persists, stop and ask a qualified professional about an appropriate exercise and range.

General guidance: Mayo Clinic on weight-training technique. Follow the specific movement steps above for this variation.

Muscles Worked

The Lying Elbow To Knee mainly targets your Abs, with your Hip Flexors helping support the movement, along with your Lower Back.

More Waist Exercises

More Abs Exercises

Equipment Alternatives

Don't have body weight? These target the same abs with different equipment.

FAQ

What muscles does the Lying Elbow To Knee work?
The Lying Elbow To Knee mainly works your abs. It also helps strengthen your hip flexors and lower back. Using good, smooth form makes sure you work the right muscles and avoid unnecessary strain on your joints.
What equipment do I need for the Lying Elbow To Knee?
You do the Lying Elbow To Knee with no equipment — just body weight. Make sure your equipment is set up safely before starting. If you work out at home or have limited gear, check out our alternative exercises below.
What form mistake should I watch for on the Lying Elbow To Knee?
One mistake to watch for is pulling the neck: For crunch variations, avoid pulling the head forward with your hands; follow the demonstrated arm and head position.. Use a comfortable range and a controlled return; reduce the load if you cannot maintain the demonstrated setup.
How many sets and reps should I perform on the Lying Elbow To Knee?
To tone and grow muscle, do 3 to 4 sets of 10 to 15 smooth reps with 60 seconds of rest, focusing on a full stretch and squeezing the muscle at the top of each rep.
What's a good alternative to the Lying Elbow To Knee?
The Assisted Hanging Knee Raise trains your abs with assisted and a similar movement pattern. Review its form guide before substituting it, since setup and range of motion can differ.
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