Skip to content

Mastering Knee Tucks: Core Strengthening Guide

Knee tucks

Getting tired of boring old crunches, well you’re in luck! Knee tucks are an easy-to-do full-core exercise that can be completed just about anywhere. If knee tucks are not currently part of your ab routine, learn how this versatile exercise could be the missing link between you and washboard abs.

Why Knee Tucks?

Sometimes referred to as “reverse crunches” knee tuck are a deep core exercise designed to resemble a hybrid between crunches and leg raises. You receive the benefits of a crunch while also targeting the hip flexor and lower abdominal muscles.


Improved strength and stability in athletics and weightlifting


Great core strengthening exercise for lower back pain 


Functional strength: reduces the risk of injury in daily activities


Improve overall balance and coordination between crucial muscle groups


Aesthetically attractive 


Great for beginner and advanced users - if you fall under the “advanced” category, try holding a dumbbell or medicine ball with your feet to challenge yourself.

Knee Tucks Tips

Getting your top apps is much easier because they are targeted in a lot more movements. The lower abdomen that are more difficult to obtain due to their location in your torso and the difficulty involved in isolating them.

The knee tuck exercise is intended to work your lower abs when done properly.

You want to lean back while maintaining a neutral posture to focus on the lower body side of the movement. Keeping a stable upper body will allow you to fixate on your lower abdomen.

Be patient, it may take a few sets to get the correct feel for the exercise, but stay slow and controlled to master the form initially.

If you're a beginner, place your hands on the ground for stability. As you progress with the movement you will be able to balance and utilize your core to the point you won’t need your hands for assistance.

For a visual, check out how to do a seated knee tuck.

Knee Tucks Muscles Worked

Knee tucks primarily work the rectus abdominis (upper abs), transverse abdominis (lower abs), obliques (outer abs), and hip flexors, along with secondary muscles such as rectus femoris (quads), hip adductors, and spinal erectors

Hanging Knee Tucks

The hanging knee tuck is a more advanced alternative to the standard knee tuck.

Improved grip strength and enhanced shoulder stability play a role in this movement, so if you’re looking for more of a full-body functional ab exercise, the hanging knee tuck could be exactly what you're looking for.

For beginners keep your knees bent and try not to sway too much. When getting accustomed to hanging knee tucks, you will learn that the movement requires a bit of a swinging rhythm to get in a consistent groove. 

When I began mixing hanging knee tucks into my routine it took a couple of sets to get used to, but now it’s one of my favorite and most beneficial core exercises in my rotation.

If you can do 10+ reps with ease, try the hanging knee tuck while keeping your legs straight or holding a weight with your feet/knees. 

Hanging knee tucks

Alternating Knee Tucks

Similar to the bicycle crunch or oblique twist, alternating knee tucks require coordination:

How to:

Start by sitting on the floor with your knees bent.

Lean back slightly and use your ab muscles to support your torso.

Place your hands loosely behind your head or at your side.

Lift your feet off the ground and balance on your butt/tailbone.

Rotate your body and bring in your left knee while straightening your right leg.

Return to the beginning position and repeat on the opposite side, with your right knee and stretching your left leg straight out.

Continue alternating sides in a smooth, steady action similar to riding a bicycle.

Maintain a moderate speed and engage your core during the action.

Alternating knee tucks benefits:

Alternating knee tucks are great because they address muscular imbalances, promote symmetrical growth, and replicate useful twisting motions found in everyday activities and sports.

Alternating knee tucks also increase flexibility in the hip flexors and lower back.

Alternating knee tucks work the oblique muscles (outer abs) more than seated knee tucks. They also allow you to do more reps making them more effective for calorie burn and helping in losing lower back fat above the buttocks.

alternating knee tucks - oblique muscle

Knee Tucks Alternatives

Leg raises and leg raise variations - designed for strengthening the core and hip flexors.

Cross-leg reverse crunch - the traditional crunch is more upper abdominals, this variation of reverse crunches will get you on the lower abdominals.

Oblique exercises - oblique muscles help tighten the belly and brace the core.

Core exercises with dumbbells - 7 of the best core exercises with dumbbells that you can use from the comfort of your living room.

Around the world abs - you’ll feel your entire core engage with this motion.

Kettlebell ab workout - 5 kettlebell ab workouts.

Oblique twists - awesome knee tucks alternative for building up the outer abs.

Ab exercise with ball - explore 10 great core exercises with a ball.

Planks, side planks, and copenhagen planks

Mcgill crunch - great exercise if you suffer from lower back pain.

Knee Tucks - FAQ

What do knee tucks work?

Knee tucks primarily work the rectus abdominis (upper abs), transverse abdominis (lower abs), obliques (outer abs), and hip flexors, along with secondary muscles such as rectus femoris (quads), hip adductors, and spinal erectors. 

How many knee tucks should I do?

You will be able to up your number of sets and reps as you progress, but a good starting point is 2-3 sets of anywhere from 8-20 reps. Once you get the form down and build up some resilience in your core, you can surpass the 20 rep mark.

How often should I train my abs?

The general rule is roughly 2-3 times a week. Abs are an important muscle group in performance as well as injury prevention which means they require proper rest time in between sessions. 48 hours between ab sessions is recommended for adequate recovery.

As you start mastering your knee tucks, check out our page on the benefits of a rectus femoris stretch!



[1] Donnelly, Joseph M. Travell, Simons & Simons Myofascial Pain and Dysfunction: the Trigger Point Manual. 3rd ed., Wolters Kluwer Health, 2019. 

[2] Davies, Clair, and Amber Davies. The Trigger Point Therapy Workbook: Your Self-Treatment Guide for Pain Relief. 3rd ed., New Harbinger Publications, Inc., 2013.

Leave a comment

Subscribe to our newsletter

Receive emails every few days with back pain relief tips, testimonials, and resources