Lying Knee Raises

Knee Raises – Easy Exercise To Start Your Core Development

Knee raises are great for starting your ab and hip flexor development. It’s one of the easiest exercises in a front lever progression.

To be clear, it’s lying knee raises. There is also a hanging knee raises version done while hanging from a pull up bar. The hanging version is harder to do.

Lying knee raises will help you build basic abs and hip strength. This will prepare your body for harder exercises like lying leg raises.

When I started I was barely able to lift my legs off the ground. My abs and hip flexors were awfully weak.

I was able to lift my upper body off the floor. Doing crunches was doable for me. Knee raises were too hard when I started.

Little by little I slowly progressed. After a month or two I was able to do lying knee raises.

What are lying knee raises?

Lying Knee Raises

Lying knee raises are a bodyweight exercise that works your core and hip muscles. This is an easy exercise suited well for beginners.

It’s performed laying on your back. You are lying flat on the ground and raising your legs bent at your knees.

If you concentrate on lifting your butt off the floor at the end of the move, you will engage your abs. If you keep your butt on the floor the whole time, you will only work your hip flexors.

Lying knee raises benefits

Lying knee raises are a great beginner exercise. It will help you begin your core development when your abs and hip flexors are still weak.

Here are the main benefits of knee raises:

  • Core strengthening: If you concentrate on the last part of the move, this exercise will help you activate your abs. This will jump start your core development. It will help you strengthen your abs.
  • Hip flexor activation: It will help you develop the strength and mobility of your hip flexors.
  • Beginner friendliness: Because it’s relatively easy to do, this exercise is well suited for beginners.


You won’t need any equipment to do lying knee raises. But, if you do it on the hard floor it may feel uncomfortable. To make it more pleasant, you may want to use an exercise mat. This is optional.

Lying knee raises equipment needed:

  • Exercise mat (optional)

Lying knee raise muscles worked

You will have to activate your hip flexors, abs, and obliques to do lying knee raises. Some additional muscles will be used to support this movement too.

Lying knee raises muscles worked:


  • Hip flexors
  • Obliques
  • Rectus abdominis


  • Quadriceps
  • Gluteus
  • Lower back

How to do lying knee raises


Lay down on your back. You should be lying flat on your back. Your pelvis should be pushed a little more down so your spine is in contact with the ground in its entirety. This will prevent your lower back injury.

Your arms should be positioned next to your body. Before starting to move, keep your legs straight with your toes pointed down. Keep your toes pointed during the move.

Upward movement:

To start knee raise, lift your heels off the ground. You should be lifting your legs off the ground by lifting your heels off the ground and bending your knees.

Pull your knees towards your body until the upper portion of your legs forms 90 degree angle to your body. The lower portion of your legs will be parallel to the ground in the uppermost position.

To activate your abs, lift your butt slightly off the floor at the very end of the move.

Downward movement:

Lower your butt back to the ground. Do this slowly. When your butt is back on the ground, slowly extend and lower your legs back.

There are two versions you can do. One is by completely lowering your legs down. This will make this exercise easier to do. It is great when you still lack strength and just starting out.

The other option is lowering your legs, but not touching the ground. You will keep your legs clear off the floor an inch or two. This is harder to do. Once you master doing it by touching the ground in each rep, you may increase the difficulty by keeping your legs off the ground.

Do these movements for reps.

Lying knee raises common mistakes

Lying knee raises are pretty easy to do. But regardless of its simplicity, there is still room for some mistakes. Here are the most common mistakes that occur and how to prevent them from happening.

Mistake 1: Not engaging abs

Not lifting your butt off the floor at the end of the move. When you raise your knees off the floor your hip flexors do most of the work. If you want your abs to kick in, you need to raise your butt off the floor at the end of the move.

To correct this mistake, make sure to lift your butt off the ground at the end of the move.

Mistake 2: Using momentum

If you use momentum to lift your knees off the ground, you are not doing it correctly. If you don’t do it slowly your muscles will not be fully activated. This will prevent you from reaping the main benefits of this exercise.

It’s easy to correct this mistake. Just use your muscles to lift your knees off the ground. Concentrate on doing it slowly.

Mistake 3: Letting your legs drop

If you don’t lower your legs down slowly, you are not using your muscles in the most important part of the move. The eccentric part of the exercise is the most important for building muscle strength and mass. This is the lowering part of the movement in knee raises. If you don’t concentrate on doing this well, you are missing the most important part of the exercise.

Letting your legs drop is a mistake similar to using momentum to lift your knees off the ground. Only this mistake is even worse. It’s because it’s done on the more important part of the move.

To avoid this mistake, you have to pay special attention to lowering your legs slowly and with control.

Mistake 4: Arching back

Your back needs to be flat on the floor. If you arch your back, you are risking your lower back injury. This is why it’s important to pay special attention to not allowing back arching.

To avoid back arching you have to position your pelvis so it’s pushed a little forward. This is called posterior pelvic tilt. With your pelvis positioned correctly your entire spine will be in contact with the floor. This will prevent lower back injury.

Progression / Regression

Lying knee raises are a beginner friendly exercise that makes it great to start your fitness journey. But, there are limited options that are easier to do than lying knee raises.

There is only one exercise easier than lying knee raises in a front lever progression. This is:

When you master knee raises it’s easy to find harder options. Here are some of the more difficult ones you can try:

Key takeaways

Lying knee raises are a great beginner friendly exercise that will build your hip and abdominal muscles. It will help you start your fitness journey and slowly build your core strength. This will make you stronger and capable of doing harder exercises.

You will be doing lying leg raises in no time.

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