How to Do an Ab Tuck

Proper Form, Variations, and Common Mistakes

ab tuck

Ben Goldstein

Also Known As: Tuck, ab tuck, bend/extend tuck, knee tuck

Targets: Abdominals, hip flexors, erector spinae

Equipment Needed: None (stability ball, dumbbell, or TRX optional for variations)

Level: Intermediate-Advanced

The tuck—or ab tuck—is a basic abdominal exercise with many variations. Almost all versions of the move target the rectus abdominis, the internal and external obliques, and the transverse abdominis. Variations that require you to stabilize the upper body also engage the erector spinae muscles that run along the spine.

Because the legs are elevated in most variations of the exercise, the hip flexors are also active during this move. The hip flexors include the rectus femoris, iliacus, psoas, iliocapsularis, and sartorius muscles. These are muscles that connect the thighs to the torso and create flexion at the hip joint.

Many people do tucks and tuck variations to get flat abs. Tucks can be included in a comprehensive workout plan to improve abdominal strength and build muscles in your midsection. But whether or not the exercise will help to flatten your belly area depends on a number of factors, including your diet. You should be an experienced exerciser to try this move as common mistakes may lead to injury.


There are a few good reasons to include a tuck in your workout routine.

Good Posture

The tuck is one of many exercises that can help you to strengthen your midsection. A strong core can help you to improve your posture.

Good posture has become increasingly important as more and more Americans are spending long hours hunched over a computer at a desk. In fact, researchers have emphasized the importance of posture-promoting exercise because the strain on the back is greater in a sitting position and working with a computer can be especially hard on the back.

While good posture requires involvement and coordination of muscles in the neck, trunk, and limbs, having a strong, stable trunk helps promote good posture because it helps to compensate for movements of the distal parts of the body.

Plank Alternative

The tuck exercise has not been specifically studied for its effectiveness or relative benefits, but the v-sit, which is incorporated into one of the most common tuck variations has been examined.

In one small 2015 study, researchers compared the v-sit to the prone plank exercise. Planks are one of the most common abdominal exercises performed. The plank engages your abdominal muscles, but also requires that you engage muscles in the back and shoulders. Study authors were interested in seeing why there is so much variation between holding times in the two exercises, even though (nearly) the same muscles are engaged.

After 10 men and 10 women were tested in each position, researchers found that there were no significant differences in activation of the rectus abdominis, external obliques, internal obliques, or lumbar erector spinae (lower back). They did, however, find that the plank was more effective at engaging the thoracic erector spinae (muscles that run along the middle to upper back) and the latissimus dorsi (wing-shaped muscles in the back).

Study authors suggested that one reason for the difference in holding times between the two exercises is the demand placed on the shoulders while in plank pose. This information may be helpful for those who have a hard time performing the plank exercise because of shoulder issues. The v-sit variation of the tuck, or perhaps even the basic tuck may be a suitable alternative.


Even if you have perfect posture and you have no problems holding the plank position, there are still reasons to add a tuck to your workout. At the very least, it can add variety to your routine and prevent boredom.

Trendy abdominal exercises go in and out of style. For years, gym-goers did hundreds of crunches to get their midsections in shape. Then ab training devices became popular, and now the plank is in vogue. Most of these exercises are effective. Each has its own pros and cons. So there's no reason not to add some variety. An ab tuck can be performed with different types of equipment or none at all to continually challenge your muscles and stay engaged in your program.

Step-By-Step Instructions

Before you try this or any exercise, you should be in good health. 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 you are first adding a tuck to your workout routine, start with the basic supported tuck. Then consider adding variations as you feel more comfortable with the move.

Basic Tuck

To prepare for the exercise, start in a seated position on a mat or on the floor. Legs should be extended in front of you.

  1. Place both hands behind your body, palms facing down and fingers facing forward (towards your toes).
  2. Lean back slightly placing some weight on your hands. The elbows will bend to allow you to shift back. Keep a long, tall spine with shoulders relaxed.
  3. Bend the knees, bringing them off the floor and drawing them in towards your chest.
  4. Keep your abdominal muscles engaged and back strong as you extend the legs to a straight position. You might lean back a little bit more as you extend the legs.
  5. Bring your knees back into the chest and repeat the sequence.

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

V-Sit Tuck

This variation of the tuck eliminates the support provided by your hands. It combines a v-sit and a boat pose (popular with those that practice yoga).

Start in a seated position on a mat or on the floor. Legs should be extended in front of you.

  1. Extend the arms and lift them so they are parallel to the floor.
  2. Lean back slightly. As you do so, you'll feel the abdominal muscles engage. Keep the arms extended. Maintain a long, tall spine with shoulders relaxed.
  3. Bend the knees and bring them off the floor so that the lower legs are parallel to the floor. This is a boat pose. It may feel challenging just to balance in this position.
  4. Keep your abdominal muscles engaged and back strong as you extend the legs to a straight position. When you do so, your body will be in a V position. You will lean back a little bit more as you extend the legs to maintain your balance.
  5. Bring your knees back into the chest and repeat the sequence.

Start by doing 5–7 repetitions. Rest for a few minutes then try another 5–7. Add repetitions as you get stronger. Once you can do 10–12 repetitions with good form, consider adding a new variation to make the v-sit tuck more challenging.

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 is very easy to round your back and slump through the spine. It can be helpful to watch your form in a mirror when you are starting out. If your back takes on a C shape, try to press the rib cage forward so the back lengthens and straightens a bit. A slight curve in the back is normal but you shouldn't feel slumped.

Keep your focus forward so that the chin doesn't drop down by the chest.

Moving Too Quickly

As you move through this exercise try to keep the movements controlled and deliberate. You'll notice that it is harder to slow the movement down. It's easier to move quickly and take short breaks at each endpoint (knees in and knees extended).

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.

Tight Neck and Shoulders

Be mindful of holding stress in the shoulder or neck area when you do this exercise. Especially with the basic version of the tuck, it is typical to let the shoulders creep up towards the ears. The neck can tighten and the exercise can become uncomfortable.

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

Modifications and Variations

Need a Modification?

There are two ways to make this movement easier. The first is to keep the feet on the floor. The simple act of moving the feet closer to your chest can activate the abdominal muscles.

To do this variation, follow the instructions for the basic tuck (with hands on the floor). When you lean back before you begin, you'll notice that some weight releases from the lower body. Keep the feet in contact with the floor (just slightly supported) as you draw them in towards the chest and extend them out.

This exercise can also be performed in a sturdy chair if you are 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. Now draw the legs up and in towards your chest as far as you can, then extend them back down. If necessary, place the feet on the floor between each repetition.

Up for a Challenge?

The best way to increase the challenge is to add resistance. You can do this by adding weight (such as a med ball or dumbbell) or by changing your position and adding bodyweight. These variations require additional equipment.

Weighted Tuck

You can add weight to your upper or lower body when performing a tuck. Each version makes the exercise more difficult.

To add weight to the lower body, place a dumbbell or a medicine ball between your feet. Perform the basic tuck or the v-sit tuck maintaining a strong back and a tight core.

To add weight to the upper body, hold a dumbbell or medicine ball in your hands at chest level. Keep the shoulders relaxed and lean back slightly. Tuck the knees in then extend them long (off the floor) as you hold the weight steady.

Stability Ball Tuck

An 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 the hands on the floor. You'll end up in a supported plank position with the ball under your shins. Maintain a strong upper body and tuck the knees in towards your chest, then extend them long and repeat. With each repetition, the ball moves closer to your shoulders and then further away.

TRX Tuck

The TRX tuck may be the most challenging variation because it requires you to maintain your balance with your feet inside the TRX cradles. Preparation can also be tricky. If you've never used TRX straps before, enlist the help of a trainer or experienced exerciser to help you get your feet in place.

To perform this variation, place your feet (with toes facing down) in the TRX cradles behind you. Lay on the floor in a prone (tummy down) position. Now lift your body into a plank position. Feet should be 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 long behind you and repeat.

Safety and Precautions

This is not the exercise to try if you have lower back problems. If you have a history of back problems speak with your healthcare provider or your physical therapist before attempting this move. You may also want to work with a trainer to make sure that you maintain good form.

Also, those with shoulder problems should exercise caution when performing variations that require you to put weight on the shoulders in plank pose.

Try It Out

Incorporate a tuck exercise into one of these bodyweight workouts.

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Article Sources
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  1. Kim D, Cho M, Park Y, Yang Y. Effect of an exercise program for posture correction on musculoskeletal painJ Phys Ther Sci. 2015;27(6):1791–1794. doi:10.1589/jpts.27.1791

  2. Ivanenko Y, Gurfinkel VS. Human postural control. Front Neurosci. 2018;12:171. Published 2018 Mar 20. doi:10.3389/fnins.2018.00171

  3. Musalem LL, Stankovic T, Glisic D, Cook GE, Beach TA. Biomechanical and electromyographic comparisons of isometric trunk flexor endurance test postures: Prone plank versus V-sit. J Appl Biomech. 2015;31(6):469-75. doi: 10.1123/jab.2014-0197