How many reps of the cross-body crunch should a beginner aim for?

Aim for 2 sets of 10 to 12 reps per side, pausing briefly at the top of each crunch before switching. Add a third set once both sides feel even and controlled, rather than speeding up the alternation.

How do I make the cross-body crunch easier or harder?

To make it easier, keep both feet flat on the floor and shorten the reach toward the knee. To make it harder, extend the non-working leg straight out a few inches off the floor, which adds an anti-extension demand to the twist.

What does the cross-body crunch train, and when is it not the best choice?

It adds rotation to a basic crunch, training the obliques alongside the rectus abdominis in a simple, no-equipment movement. It is not the best choice once you need real loaded rotation for strength or size, since bodyweight twists top out quickly without added resistance.

Beginner

Cross-Body Crunch

The cross-body crunch adds rotation to the basic crunch by bringing one elbow toward the opposite knee, which recruits the external obliques alongside the rectus abdominis. Unlike the fast pedaling of a bicycle crunch, this version pauses each rep so you control the twist. It is a straightforward, no-equipment way to train the side abs.

Equipment: Body Weight
Body part: Abs
Type: Strength
Browse by muscle: Abdominal External Oblique
Browse by movement: Rotation, Spinal Flexion

How to do it

1
Lie on your back with knees bent and hands lightly behind your head.
2
Brace the core and set the low back into the floor.
3
Exhale and crunch up while rotating one elbow toward the opposite knee.
4
Draw that knee slightly in to meet the elbow at the top.
5
Inhale and lower back to the floor under control.
6
Alternate sides with each rep at a controlled pace.

Tips

Rotate through the trunk so the elbow travels across, not just up.
Keep the hand behind the head as light support and avoid yanking the neck.
Pause and squeeze each rep rather than rushing side to side.

Variations

Common mistakes

The opposite knee pulls all the way in to meet the elbow rather than rising slightly, so the hip flexors do the traveling instead of the trunk rotating.
Both feet lift off the floor together as the trunk crunches, adding a leg raise the exercise was never meant to include.
One side gets more reps than the other before you remember to switch, building the twist unevenly across a set.
The low back arches away from the floor between reps instead of staying pressed down, losing the brace right as the next rep begins.
The reaching elbow drops toward the floor on the way down instead of returning under control, giving away the tension built on the way up.

Frequently asked

How many reps of the cross-body crunch should a beginner aim for?: Aim for 2 sets of 10 to 12 reps per side, pausing briefly at the top of each crunch before switching. Add a third set once both sides feel even and controlled, rather than speeding up the alternation.
How do I make the cross-body crunch easier or harder?: To make it easier, keep both feet flat on the floor and shorten the reach toward the knee. To make it harder, extend the non-working leg straight out a few inches off the floor, which adds an anti-extension demand to the twist.
What does the cross-body crunch train, and when is it not the best choice?: It adds rotation to a basic crunch, training the obliques alongside the rectus abdominis in a simple, no-equipment movement. It is not the best choice once you need real loaded rotation for strength or size, since bodyweight twists top out quickly without added resistance.

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