Waist Exercise · Body Weight
3/4 Sit-Up
The 3/4 sit-up trims the range of a full sit-up so the abs stay under tension longer instead of resting at the top. Cutting the rep short keeps the lower back off the floor and the hip flexors doing less of the lifting, which is the main complaint with full sit-ups. It's a reasonable middle ground if crunches feel too short and full sit-ups feel like your hips are doing the work.
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- Waist
- Equipment
- Body Weight
- Target
- Abs
Exercise reference published by PlanWorkouts; see our editorial standards.
How to Do the 3/4 Sit-Up
- Lie on your back, bend your knees, and plant your feet flat on the floor.
- Rest your hands behind your head, letting your elbows flare out to the sides.
- Brace your abs and curl your upper body off the floor slowly, rising until your torso reaches roughly a 45-degree angle.
- Hold briefly at the top of the movement, then ease your upper body back down to where you started.
- Perform for your targeted rep count, focusing on a deliberate tempo and maximum tension in the abs.
Quick Exercise Facts
Practice and progression
Choose a short set of controlled repetitions or a manageable hold, following this movement's setup. End the set when you lose the demonstrated position. Build control before increasing repetitions, duration or resistance; holds, carries and moving drills need different prescriptions.
Technique & Form Tips
Focus on trunk flexion, rotation, or anti-movement stability as required by your specific variation. Maintain the suggested pelvic and spinal orientation to keep tension focused on the abdominal area throughout each repetition or hold.
Common Mistakes to Avoid
- Copying the wrong trunk action: Follow the demonstrated movement. A held plank, rotation and crunch require different actions rather than the same repeated trunk curl.
- Lower back arching: Keep the spine controlled to prevent the lower back from hyperextending under the load.
- Excessive speed: Perform movements with deliberate control rather than relying on rapid, bouncing motions.
How to Breathe During This Exercise
Maintain a steady breathing rhythm during the effort.
Add the 3/4 Sit-Up to Your Custom Workout Routine
Build a personalized, science-backed workout plan matching your training goals, equipment access, and schedule.
Comfort and Control
Choose a load and range you can control. Stop if the movement causes pain. If discomfort persists, stop and ask a qualified professional about an appropriate exercise and range.
General guidance: Mayo Clinic on weight-training technique. Follow the specific movement steps above for this variation.
Muscles Worked
The 3/4 Sit-Up mainly targets your Abs, with your Hip Flexors helping support the movement, along with your Lower Back.
More Waist Exercises
45° Side Bend
Air Bike
Alternate Heel Touchers
Arm Slingers Hanging Bent Knee Legs
Arm Slingers Hanging Straight Legs
Arms Overhead Full Sit-Up (male)
More Abs Exercises
Assisted Hanging Knee Raise
Assisted Hanging Knee Raise With Throw Down
Assisted Lying Leg Raise With Lateral Throw Down
Assisted Lying Leg Raise With Throw Down
Assisted Motion Russian Twist
Assisted Prone Rectus Femoris Stretch
Equipment Alternatives
Don't have body weight? These target the same abs with different equipment.
Assisted Hanging Knee Raise
Assisted Motion Russian Twist
Band Alternating V-Up
Barbell Press Sit-Up
Featured in Curated Workouts
Train the 3/4 Sit-Up with structured progression in these complete workout routines:
Iron Core 15-Minute Ab Sculpt Routine
Targeted abdominal and anti-rotation circuit building trunk stability, deep core endurance, and abdominal definition.
Living Room Lower Body & Glute Burn
High-volume bodyweight quad, hamstring, and glute workout for athletic leg stamina.
Dynamic Morning Joint Mobility & Flow
15-minute awakening routine to relieve stiffness, mobilize hips, and activate the core.
FAQ
- What muscles does the 3/4 Sit-Up work?
- The 3/4 Sit-Up mainly works your abs. It also helps strengthen your hip flexors and lower back. Using good, smooth form makes sure you work the right muscles and avoid unnecessary strain on your joints.
- What equipment do I need for the 3/4 Sit-Up?
- You do the 3/4 Sit-Up with no equipment — just body weight. Make sure your equipment is set up safely before starting. If you work out at home or have limited gear, check out our alternative exercises below.
- What form mistake should I watch for on the 3/4 Sit-Up?
- One mistake to watch for is copying the wrong trunk action: Follow the demonstrated movement. A held plank, rotation and crunch require different actions rather than the same repeated trunk curl.. Use a comfortable range and a controlled return; reduce the load if you cannot maintain the demonstrated setup.
- How many sets and reps should I perform on the 3/4 Sit-Up?
- Use a short set of controlled repetitions, or a manageable hold when the movement is static. Stop when you cannot maintain the demonstrated position. Build control before adding duration, repetitions or resistance; the appropriate amount depends on the exercise and your experience.
- What's a good alternative to the 3/4 Sit-Up?
- The Assisted Hanging Knee Raise trains your abs with assisted and a similar movement pattern. Review its form guide before substituting it, since setup and range of motion can differ.