Written by Paulina Kairys | BSKin & EX.Sc., NASM CPT
Fact checked by Kirsten Yovino, CPT Brookbush Institute
FACT CHECKED
Some of the best and most efficient abs exercises require nothing more than your bodyweight. Your bodyweight is a useful source of resistance and it allows you to train anywhere, anytime. There are hundreds of ab exercises, yet most people prefer the simplicity of standard ab crunches and sit ups. While there’s nothing wrong with the standard crunch and crunch variations, they can lose their effectiveness over time if done too often. Let’s explore an efficient ab exercise, the in and out, which is also called the seated tuck.
WHAT IS THE IN AND OUT ABS EXERCISE?
The in and out is an abdominal exercise that targets the ab muscles, hip flexors and quadriceps. This movement is mainly used to isolate the abs and can be regressed or progressed in a number of ways. The standard in and out abs exercise is advanced and challenges not only the musculature but full body stability and coordination. It may take some practice and time to build up the proper strength within the core to execute the full in and out position. When it’s done correctly, the entire body will benefit from this movement and its full-body engagement. A great bonus to this movement is that it’s very accessible because it requires no equipment and can be done anywhere.
IN AND OUT MUSCLES WORKED:
Unsurprisingly, the in and out exercise works mostly the abdominal muscles - the rectus abdominis, transverse abdominis and obliques. Holding proper form and posture for the in and out abs exercise requires activation from the lower back and hip flexors. The quadriceps muscles assist to extend and bend the legs to transition from “in” and the “out” position. Let’s break down each muscle group that the in and out targets:
- Rectus Abdominis: This muscle is the most predominant muscle of your core and is the notoriously visible 6-pack in lean individuals. It lies flat on the front side of your abdomen. It’s the prime mover of the in and out exercise, pulling your body into flexion (or inwards) and lengthening as your body extends. The rectus abdominis’ primary function is to flex your spine. The in and out abs exercise is great for both the upper abs and lower abs.
- Transversus Abdominis: The transversus abdominis’ fibers run horizontally between the ribs and pelvis, wrapping all the way around the trunk. This muscle is the deepest abdominal muscle of the 6. With the in and out, the transversus abdominis stabilizes your trunk (like a weightlifting belt) while contracting to generate intra abdominal pressure. This pressure is crucial to protect your spine in all exercises, both body weight and resisted exercises.
- Obliques: These muscles are in charge of rotating and laterally flexing your spine. Although there isn’t much rotation during the in and out, the obliques are in charge of stabilizing your upper body to prevent unwanted rotation. There are many exercises that directly target the obliques like a seated russian twist.
- Iliopsoas: The iliopsoas is the main hip flexor muscle and can be further broken down to the iliacus and psoas major muscles. This muscle group, also known as the hip flexors, activate during in and outs to help move the legs into position (flexion and extension of the hips).
- Rectus Femoris: It is one of the four quadriceps muscles and works with the hip flexors to flex the hips during the in and outs. To keep the legs in control during the exercise, activating through the quadriceps and keeping the legs close together helps a smooth transition from one repetition to the next.
With most isolation exercises, it takes time to feel the benefits of increased strength of the muscles involved. Incorporate the in and out abs movement regularly into your fitness program to see gradual progress. As you grow accustomed to the movement, start to incorporate progressed versions of the in and out abs exercise to challenge your strength.
HOW TO DO THE IN AND OUT ABS EXERCISE?
This “how to” is based on a standard in and out which is an advanced version. Regressions and progressions to the in and out exercise are listed below.
- Start in a seated, upright position on the floor with your knees bent, feet flat on the ground and legs close together. If you need an exercise mat, be sure to sit on that.
- Keeping your upright seated position, lift your arms out in front of you and lift your feet off of the ground. This is your starting position.
- Draw your knees to your chest and contract your abdominals and hip flexors to keep your body stable. This is the “in” portion of your in and out.
- Next, lean your torso back sand simultaneously extend your legs out in front of you. This will counterbalance your position and make sure that your torso is leaning back while your legs are hovering above the ground.
- Keep your abs contracted to support your lower back as well as your posture. Retract your chin to protect your neck.
- As soon as you feel a deep stretch within your core, hold the “out” position for one count. Keep your core tight with your legs extended.
- From there, reverse back into your “in” position with your legs bent by lifting your torso to your center line and drawing your knees towards your chest.
- Repeat the in and out with control and stability.
COMMON MISTAKES WHEN DOING THE IN AND OUT ABS EXERCISE
The most common mistakes for the in and out exercise mostly revolve around jumping into an advanced version of the movement. Utilize a regressed version of the in and out if you notice the following mistakes:
- Excessively rounding through the back: Throughout the exercise, make sure to keep a neutral spine (spine straight). Think about lengthening through the top of your head all the way to your toes as you move from each landmark. Retract your chin to reduce the strain of your neck.
- Reaching all the way to the ground: At the bottom of your “out” position, make sure to keep your shoulder blades, mid back and legs from touching down to the ground. Reaching all the way down to the ground will lose the activation of your core and can strain the lower back when the core brace is lost.
- Holding your breath: It is so easy to forget about proper breathing mechanics while training the core muscles. Yes, the in and out is hard BUT breathing will make it feel a lot more in sync. Take a big inhale as you extend into the “out” position and forcefully exhale as your contract and come to the centerline of the “in” position.
- Losing balance: Full body tension will help you keep your balance during the in and out exercise. Keeping the legs close together, activating your lower body, bracing through your entire core, and actively reaching your arms forwards are all factors to consider when activating your entire body. If you still find yourself falling out of correct form, place your hands on the ground for additional support. When you’re ready, lift your arms out in front of you for a challenge.
IN AND OUT REGRESSION AND PROGRESSION AB EXERCISES
Below are some good regression exercises (if the in and out abs exercise is too difficult) and progression exercises (if the in and out exercise is too easy).
Regression abs exercises:
- Supported In and Out: The most simple regression to the in and out is accessing additional support by setting your hands on the ground and repeating the movement just with your lower body. Your hands will help ground your position so you can focus more on the activation of your core. From there, you can also try a wide arm position with your hands off the ground. This would be the next progression after doing the in and out abs exercise with your hands on the ground.
- Static Half V Sit: Similar to the “in” position, sit tall and stack your spine. Bend through the knees and lift your feet off of the ground. Slightly lean your torso back, lift your feet so they’re even with eye level and hold this v like sitting position. Keep your core tight the entire hold. The static v sit teaches you how to balance and activate through your body, similarly to a static plank.
- Reverse Crunch: Lying flat on your back, bend both knees and lift your legs into a table top position. Breathe and brace into your lower abdominals and lower your table top to the ground. Tap your heels down to the ground then use your abdominals to pull your legs back into tabletop. Keep a straight spine the entire time. This movement isolates your core and lower body and is a great starting point to connect with your lower belly brace.
Progression ab exercises:
- Overhead In and Out: Instead of actively reaching your arms forwards, lift them up and overhead as you repeat your in and outs. This simple switch will shift your center of gravity and challenge your ability to stabilize the movement.
- Weighted In and Out: Attach ankle weights or balance a small weighted plate or medicine ball on your shins for additional resistance. The weights will be pulling your legs towards the ground, resist the weights and make sure to brace through your core to protect the lower back.
- Full V Sit Up: Place an exercise mat down on the floor then lie on your back with your legs straight and your arms extended above you. From there, raise your legs up while simultaneously raising your upper body off the ground so that your hands meet your feet at your centerline. Essentially, you are creating a "V" with your body. Keep your butt to the ground and your spine straight at all times. Slowly lower back to the fully extended lying position, but don't let your feet or hands touch the ground, and repeat. This is an incredible exercise for your upper abs and lower abs. It's one of the most challenging body weight ab exercises.
Bonus exercise: If you have a pull up bar, hanging knee raises and hanging leg raises are fantastic lower ab movements.
BENEFITS & DRAWBACKS OF IN AND OUTS
In and out abs exercises are definitely worthy of your core workouts. To sum things up, let's look at the benefits of adding in and outs to your routine:
- Strengthens the core: Isolating and strengthening the core muscles leads to stronger functional movements both in and out of the gym. A strong core also helps with balance, posture and stability.
- Accessible bodyweight exercise: The in and out is popular due to its accessibility and practicality. You can do this movement essentially wherever without investing in equipment! The regressions and progressions of this movement also include many popular bodyweight exercise options.
- Hip strengthening exercise: Prolonged sitting can lead to underactive and weak hip flexors. The hip flexors are a big component to achieving a proper in and out position. Strengthening this muscle group will lead to improved muscle connection of the lower body.
While there are many benefits of the in and out exercise, there are a few drawbacks to recognize:
- Lower back muscle fatigue: The iliacus and psoas major (part of hip flexor muscle group) attach to the lumbar vertebrae. When the transversus abdominis is failing to activate and stabilize the lower back, the hip flexors can pull the lower back in an overly extended position. A strong transversus abdominis will protect your lower back and reduce the stress. Practicing in and outs at a smaller capacity while properly bracing can ensure a reduced risk of lower back fatigue.
- Limited progressive overload: As you gain strength in your in and outs, it may be harder to keep progressing this movement with just bodyweight. You may be stuck with only one option to increase the intensity: doing more reps. High rep training is not the best solution to directly strengthen your abdominals.
If you have questions about in and outs, please feel free to leave a comment below.
You can also work your abs from a standing position! Here is a great standing abs workout for you to follow along to.
Other Exercises for Your Abs:
- Best Upper Ab Exercises
- Best Lower Ab Exercises
- Best Oblique Exercises
- Weight Bench Ab Exercises
- Dumbbell Ab Exercises
- Cable Machine Ab Exercises
- Abdominal Stretches
Paulina Kairys
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