How to do the In and Out Abs Exercise Correctly

Bodyweight ab training doesn’t have to mean endless crunches. The in & out (aka seated tuck) is a compact, no-equipment move that hits the rectus abdominis, deep core, hip flexors, and quads while challenging balance and coordination. Do it right, and you’ll build a stronger brace for lifting—and a mean lower-ab burn.

In this guide you’ll learn:

• What the in & out is and who it’s for
• Muscles worked (and why it lights up your lower abs)
• Perfect form: step-by-step with cues
• Common mistakes (and simple fixes)
• Regressions if it’s too hard & progressions if it’s too easy
• Benefits, drawbacks, and how to program it into your week
• Quick FAQs and related SFS resources

WHAT IS THE IN AND OUT ABS EXERCISE?

The in & out is a bodyweight abdominal exercise performed in a seated position. You’ll pull the knees toward the chest (“in”) and extend the legs while leaning the torso back (“out”)—maintaining a neutral spine and a tight brace throughout. It can be scaled for beginners or loaded/challenged for advanced athletes.

IN AND OUT MUSCLES WORKED:

• Rectus Abdominis (six-pack): Primary mover—flexes the spine as you tuck; lengthens under control as you extend.
• Transversus Abdominis (TVA): Deep “belt” that stabilizes the trunk and protects the lumbar spine via intra-abdominal pressure.
• Obliques: Resist unwanted rotation and side-bending; keep the torso square during movement.
• Hip Flexors (Iliopsoas): Assist knee/hip movement between “in” and “out.”
• Rectus Femoris (Quads): Helps control leg extension and keeps the legs “long” and organized.

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.

1. 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.
2. 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.
3. 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.
4. 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. 
5. Keep your abs contracted to support your lower back as well as your posture. Retract your chin to protect your neck. 
6. 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.
7. 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. 
8. Repeat the in and out with control and stability.

COMMON MISTAKES WHEN DOING THE IN AND OUT ABS EXERCISE

• Rounding the back: Keep the ribcage stacked over the pelvis; imagine a string lifting your sternum. Fix: Soften range, add floor support with hands.
• Leaning all the way to the ground: Losing tension between reps strains the low back. Fix: Keep shoulder blades and heels hovering.
• Holding your breath: Bracing ≠ breath-holding. Fix: Inhale to extend, forceful exhale to tuck.
• Losing balance: Wide base with fingertips on the floor, legs pressed lightly together, and reach the arms forward. Fix: Slow down; tension from toes to fingertips.

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 & Outs: Hands on the floor behind you for balance; same leg path.
• Static Half V-Sit Hold: Shins parallel, torso slightly back, hold 10–20s with perfect posture.
• Reverse Crunch (on floor): Knees to chest from tabletop; focus on posterior pelvic tilt and slow eccentric.
  

Progression ab exercises:

• Overhead In & Outs: Arms overhead to shift lever and challenge brace.
• Weighted In & Outs: Light ankle weights or medicine ball on shins.
• Full V-Sit (V-Up): From supine, raise legs and torso to meet at the midline; control the descent.
  • Bonus: Hanging knee/leg raises for lower-ab bias if you have a bar.
    

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:

• Stronger brace for squats, deadlifts, presses.
• No equipment and minimal space needed.
• Hits lower-ab sensation many lifters chase, with balance and coordination.
  

While there are many benefits of the in and out exercise, there are a few drawbacks to recognize:

• Low-back fatigue if hip flexors dominate or you over-extend. Start with regressions and master the brace.
• Limited overload with bodyweight alone—use progressions/load over time.
  

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.

Programming: Sets, Reps & Placement

• Beginners: 2–3 sets of 6–10 controlled reps, 2–3x/week.
• Intermediate: 3–4 sets of 10–15 reps, or 30–45s timed sets.
• Advanced: 3–4 sets of 12–20 reps or weighted; superset with anti-rotation work (Pallof press).
• Where to place: After your main lifts as a core accessory, or in GPP/conditioning circuits.
• Tempo: 2–0–2 (two seconds in, no pause, two seconds out) or a brief 1-count hold extended.

FAQs

Q: I feel this in my hip flexors more than my abs.
A: Reduce range, switch to supported in & outs, and cue ribs down + slight posterior pelvic tilt. Sprinkle in reverse crunches to groove the pattern.

Q: Lower-back discomfort—stop or modify?
A: Stop the set and regress. If discomfort persists, skip this movement and substitute dead bugs or hollow holds until bracing improves.

Q: How do I make it harder without hurting form?
A: Raise arms overhead, add light load, slow the tempo, or pause in the extended position.

Safety & Form Notes

• Warm up with cat-camel, dead bug, and glute bridges to prep the trunk.
• Keep neck neutral (slight chin tuck), eyes forward.
• Pain ≠ progress—swap to a regression if any joint discomfort shows up.

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