Target tension.: Whether the muscle you’re training is what gives out first, not your grip, balance or other muscles.
Loaded stretch.: How hard the muscle works while stretched. Training it there is linked to more growth.
Progression.: How easily you can keep adding weight in small steps over months and years.
Low cost.: How easy it is on your joints and recovery, and how quickly you can learn it.

The research score comes from these, scored by hand from the studies. Lifter scores appear once an exercise has 10 ratings. How scores work

When each one fits

Good reasons to choose crunch

You have no equipment
You want something easier on your joints

Good reasons to choose decline sit-up

You want to keep adding weight in small steps
You want more load on the abs while they’re stretched

Crunch

Decline Sit-Up

You need

Nothing but the floor

Bench

Skill

Easy to learn

Type

Isolation

Questions

Which is better for your abs, crunch or decline sit-up?

For your abs, decline sit-up rates well ahead on our research criteria: easier to progress, more stretch. Crunch is easier on the joints.

Is crunch or decline sit-up easier to learn?

About the same: both are easy to learn.

Can you do crunch or decline sit-up at home?

Crunch needs no equipment, so you can do it anywhere. Decline sit-up needs a bench, so a home gym covers it.

Which is easier on the joints, crunch or decline sit-up?

Crunch: it rates Excellent for joint and recovery cost in our research rubric, against Strong for decline sit-up.

More comparisons

Crunch Decline Sit-Up All abs exercises

Crunch vs Decline Sit-Up

For your abs, decline sit-up rates well ahead on our research criteria: easier to progress, more stretch.

Crunch is easier on the joints.

What these mean

Target tension.: Whether the muscle you’re training is what gives out first, not your grip, balance or other muscles.
Loaded stretch.: How hard the muscle works while stretched. Training it there is linked to more growth.
Progression.: How easily you can keep adding weight in small steps over months and years.
Low cost.: How easy it is on your joints and recovery, and how quickly you can learn it.