Straight Leg Situps

Straight Leg Sit-Ups (How To & Alternatives)

Straight Leg Sit-ups are a slight variation of one of the tried and true ‘classic’ core exercises. Basically, instead of bending the knees and placing feet on the floor the legs are kept straight and lying flat on the ground.

In this guide, I’m going to teach you how to properly do Straight Leg Sit-ups, explain what muscles they work and provide a few alternatives.

How To Do Straight Leg Sit-Ups

Equipment Needed

  • None

Step-by-Step Instructions

  • Lay on your back, leaving your legs straight and flat on the ground.
  • Place your hands either behind your head for support, besides the ears or arms crossed in front of the chest.
  • Sit up by contracting and flexing the abdominals until your torso becomes perpendicular to the ground. (sitting straight up)
  • Lower back down to the floor and repeat for the designated number of reps.

Coaching Points

The biggest mistake that I see with Straight Leg Sit-ups is essentially the same mistake that I see with regular Sit-ups. It is pulling way too hard on the back of the head. If you are going to place your hands behind your head, do so only to support the head, not pull on it.

Instead of placing the hands behind the head you can also keep hands by the ears, or in front of the chest if needed, but avoid pulling on the back of the head.

Muscles Worked

Straight Leg Sit-ups work the entire abdominal region but primarily emphasize the rectus abdominis.

Straight Leg Sit-Up Alternatives

If you’re unable to do Straight Leg Sit-ups, here are a few alternatives that you may be able to use as a substitution.


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.

Sky Crunches

Sky Crunches are probably the best beginner-friendly progression to get you prepared to do Straight Leg Situps. You start in basically the exact same position – laying on your back with legs straight.

However, instead of sitting all the way up, you simply crunch up towards the sky (hence ‘sky crunches’).

More Links and Info

For more ab exercises with step-by-step instructions, check out the Core Section of the Exercise Library

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