Sit-Ups (How To, Muscles Worked, Benefits)

Sit-Ups are a classic core exercise that targets the rectus abdominis by taking your torso through a full range of motion. Unlike crunches, sit-ups involve lifting your entire upper body off the floor, engaging both your abs and hip flexors.

This movement is simple and effective for building core strength and endurance when done with proper form.

Primary Muscles Worked: Rectus Abdominis
Secondary Muscles Worked: Obliques, Hip Flexors
Equipment Needed: None (optional mat or foot anchor for support)

How To Do Sit-Ups

Step-by-Step Instructions

Set-Up:
- Lie on your back with your knees bent and feet flat on the floor, hip-width apart.
- Cross your arms over your chest or place your fingertips lightly behind your ears (avoid pulling on your neck).
- Keep your lower back pressed lightly into the floor and engage your core.
Execution:
- Use your abdominal muscles to lift your upper body off the ground toward your knees.
- Sit all the way up until your chest is over your hips.
- Slowly lower yourself back down to the floor with control, keeping tension in your abs.
Tips for Proper Form:
- Avoid using momentum—move with control.
- Keep your feet grounded and don’t let them lift off the floor.
- Exhale at the top, inhale on the way down.

Key Benefits

Strengthens the full abdominal wall with a full range of motion.
Builds core endurance and body control.
Easy to perform anywhere with no equipment.

Modifications and Variations

Easier Option: Use a foot anchor or have someone hold your feet for support.
Harder Option: Hold a plate or dumbbell at your chest, or perform on a decline bench for more resistance.

Common Mistakes

Pulling on the Neck: If your hands are behind your head, keep your elbows wide and don’t tug forward.
Using Momentum: Keep it slow and deliberate for better activation.
Incomplete Range of Motion: Sit all the way up and control the descent.

Reps and Sets Recommendations

For Beginners: 3 sets of 10–12 reps, focusing on technique.
For Core Strength/Endurance: 3–4 sets of 15–20 reps.
With Resistance: 3 sets of 8–10 reps using a weight plate or dumbbell at your chest.

Sit-Up Alternatives

If you’re unable to do Sit-ups, here are a few alternatives that you may be able to use as a substitution. Want even more options? Here are 17 alternatives to Sit-ups to work your core.

Crunches

The simplest alternative to Sit-ups is to switch them out for Crunches. If you’re struggling with Sit-ups, Crunches is the first thing I would suggest as a replacement until you’re ready to progress back to Sit-ups.

Start laying on your back as well, knees bent at 90 and feet off the floor. Instead of sitting all the way up, simply crunch up and squeeze the abs.

Suitcase Crunches

Another alternative for Sit-ups are Suitcase Crunches. These are a little more difficult than regular Crunches, so they can be used as a progression toward doing full Sit-ups.

Instead of laying on your back, balance up on your butt and bring your knees and chest together at the top and then extend out – keeping back and feet off the ground throughout the entire set.