Lying Crunch (straight Legs)

1. Lie on your back on a mat with the legs straight, feet together and heels resting on the floor.
2. Place the hands lightly beside the ears or crossed on the chest.
3. Press the lower back gently into the floor and tuck the chin slightly.
4. Exhale and curl the shoulders and upper back off the mat, bringing the ribs toward the pelvis.
5. Stop when the shoulder blades are clear of the floor and squeeze the abs for a count.
6. Lower slowly over two seconds until the shoulders touch the mat again.
7. Repeat for the planned reps, keeping the legs still and relaxed.

Common Mistakes

• Legs lifting off floor: The feet rising shows the hip flexors are pulling. Keep the legs heavy on the mat and shorten the crunch if needed.
• Pulling with the hands: Yanking the head strains the neck and cheats the abs. Keep the hands light and lead with the chest.
• Crunching too high: Trying to sit all the way up involves the hip flexors and back. Lift only until the shoulder blades clear the floor.

Programming Tips

Perform 3 to 4 sets of 15 to 25 reps at the end of a workout or in a core circuit. It is a rectus abdominis isolation move that works well for beginners and for anyone whose hip flexors dominate bent knee crunches.

Lie flat with the legs together and the lower back pressed into the mat. Bodyweight is the load; progress by adding a two-second hold at the top, slowing the lowering to three seconds, or holding a 2.5 to 5 kg plate on the chest. The most common fault is the lower back arching and the legs lifting; fix it by exhaling fully at the top and keeping the heels glued down.

Common Questions

What muscles does the straight leg crunch work?

It works the rectus abdominis primarily with the obliques assisting. The hip flexors contribute much less than in a sit up because the legs stay on the floor.

Is a crunch with straight legs better than bent knees?

Straight legs reduce hip flexor help and make the abs work harder through a short range, while bent knees are more comfortable for the lower back. Use straight legs if you feel crunches in the hips rather than the abs.

How many crunches should I do a day?

Three or four sets of 15 to 25 slow reps a few times a week is enough; daily high-volume crunching adds little. Strength and visibility of the abs depend more on diet and heavy compound lifts.