How to Do Ab Tucks: Proper Form, Variations, and Common Mistakes

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The ab tuck is an abdominal exercise with many variations. It's meant for more experienced exercisers since it takes a higher level of strength in the torso to perform. If you're at this fitness level, consider including ab tucks in your core strengthening routine.

Also Known As: Tuck, bend-extend tuck, knee tuck, seated knee tuck

Targets: Abdominals and hip flexors

Equipment Needed: Exercise mat (optional)

Level: Intermediate to advanced

How to Do an Ab Tuck

Verywell / Ben Goldstein

Start in a seated position on an exercise mat or the floor. Your legs are extended in front of you with both hands behind your body, palms facing down and fingers facing forward (toward your toes).

Lean back slightly and engage your core while placing some weight on your hands. The elbows will bend to allow you to shift back. Keep a long, tall spine with the shoulders relaxed. This is the starting position.

  1. Bend the knees, bringing them off the floor and drawing them toward your chest. At the same time, bring your hands up, next to your thighs and buttocks.
  2. Extend the legs so the hips are at a 45-degree angle while moving your arms over your head as if reaching for something behind you.
  3. Bring your knees back into the chest and repeat the sequence.
  4. Lower the legs and arms to the floor once you're ready to end this exercise.

Keep your abdominal muscles engaged and back strong throughout the movement.

Benefits of the Ab Tuck

The ab tuck targets the rectus abdominis, internal and external obliques, and transverse abdominis muscles. Because the legs are elevated, the hip flexors are also active during this move. The ab tuck strengthens these muscles, and can add variety to your exercise routine and prevent workout boredom.

The tuck is one of many exercises that can help you to strengthen your midsection, which can improve your posture. This is important if you spend long hours hunched over a laptop or at a computer desk, as this can place a lot of strain on the back.

Ab tucks also serve a functional purpose. For instance, they help you build the core strength needed to perform everyday activities such as putting groceries away, vacuuming, or lifting a heavier item to place it on a high shelf.

Some people do tucks to get flat abs. However, whether or not the exercise will help to flatten your belly depends on a number of factors, including your diet.

Other Variations of the Ab Tuck

You can perform this exercise in different ways to better meet your fitness level and goals.

Stationary Arms

If you want to make this movement easier, don't move your arms. Instead, keep them on the floor behind you and use them to support your upper body when bringing the knees in and extending the legs. This takes some of the pressure off your core.

Feet on the Floor

Another modification that can make this exercise less challenging is to keep your feet on the floor. To do this variation, keep the feet in contact with the floor (just slightly supported) as you draw them toward the chest and extend them out.

Chair Ab Tuck

This exercise can also be performed in a sturdy chair if you're not comfortable getting onto the floor. Once seated, place hands on the sides of the chair or the armrests, scoot forward just a bit and lean back slightly. Next, draw the legs toward your chest as far as you can before extending them back down.

If you struggle to complete these tuck variations, it may help to place your feet on the floor between each repetition.

Weighted Ab Tuck

Increase the challenge of this exercise by adding resistance. You can do this by adding weight, such as with a medicine ball or dumbbell. Hold the weight at chest level and perform the movement in this position.

Alternatively, you can add weight to the lower body instead by holding a dumbbell or medicine ball between your feet. This does require even greater core and lower body strength, so you may need to work up to this variation.

Stability Ball Tuck

The ab tuck can be performed in a prone position on a stability ball. Begin by kneeling in front of the ball. Roll your torso forward and over the ball, placing your hands on the floor. This puts you in a supported plank position with the ball under your shins.

Maintain a strong upper body and tuck the knees in toward your chest, then extend your legs and repeat. With each repetition, the ball moves closer to your shoulders and then further away.

V-Sit Tuck

This variation combines a v-sit and boat pose (which you may have done in a yoga class). Start in a seated position, legs extended in front of you. Extend the arms and lift them so they are parallel to the floor, then lean back slightly.

Bend the knees and lift the lower legs until they are parallel to the floor. This is a boat pose. Keep your abdominal muscles engaged and back strong as you extend the legs to a straight position (your body will be in a V position). Bring your knees back into the chest and repeat the sequence.

TRX Tuck

The TRX tuck may be the most challenging variation because it requires you to maintain your balance with your feet inside TRX cradles. To perform this exercise, place your feet—toes facing down—in the TRX cradles behind you, then lay on the floor in a prone (tummy down) position.

Lift your body into a plank position with your feet elevated at shoulder height in the cradles. Maintain a strong core and stable upper body as you pull the knees into your chest. Extend the legs behind you and repeat.

Preparation for this tuck variation can be tricky. If you've never used TRX straps before, enlist the help of a personal trainer or experienced exerciser to help you get your feet in place.

Common Mistakes

There are a few common blunders to watch for when doing the tuck exercise.

Slumped Back

When you first learn this exercise, it's easy to round your back and slump through the spine. A slight curve is normal, but you shouldn't feel slumped.

It can be helpful to watch your form in a mirror when starting out. If your back takes on a C shape, press the rib cage forward so the spine lengthens and straightens a bit. Also, keep your focus forward so the chin doesn't drop down by the chest.

Moving Too Quickly

It's easy to move quickly through this exercise, taking short breaks at each endpoint (knees in and knees extended). Slowing the movement can feel much harder. Yet, as you move through this exercise, you want to keep the movements controlled and deliberate.

To help keep the movement steady, focus on your breathing. Count to three as you extend the legs and exhale, then count to three as you pull the legs in and inhale. This tempo will prevent you from moving too fast.

Tight Neck and Shoulders

It's typical to let the shoulders creep up toward the ears, especially with the basic tuck. So, be mindful of holding stress in the shoulder or neck area when you do this exercise as the neck can tighten, making the exercise uncomfortable.

Each time you exhale, think about creating space between the shoulders and the ears to keep the upper body relaxed.

Safety and Precautions

If you have a history of back problems, speak with your healthcare provider or physical therapist before attempting this move. Those with shoulder problems should exercise caution when performing variations that require you to put weight on the shoulders in a plank pose.

If you feel pain in the back, shoulders, or hips, stop the movement immediately. While some level of discomfort or "burn" is normal during this intermediate-to-advanced exercise, pain is not.

Always seek the guidance of your healthcare provider if you are new to exercise or if you are coming back to exercise after an injury. You can also work with a qualified fitness trainer to get form tips and exercise advice.

When first learning the basic tuck, try doing 5 to 7 repetitions, rest for a few minutes, then do another 5 to 7. Add repetitions as you get stronger. Once you can do 10 to 12 reps with good form, consider adding a variation to make the tuck more challenging.

Try It Out

Incorporate this move and similar ones into one of these popular workouts:

3 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Malia Frey, M.A., ACE-CHC, CPT
 Malia Frey is a weight loss expert, certified health coach, weight management specialist, personal trainer​, and fitness nutrition specialist.