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

Crunch

Reverse Crunch

You need

Nothing but the floor

Skill

Easy to learn

Type

Isolation

Questions

Which is better for your abs, crunch or reverse crunch?

For your abs, crunch and reverse crunch score the same on every criterion, so use whichever is free, or both.

Is crunch or reverse crunch easier to learn?

About the same: both are easy to learn.

Can you do crunch or reverse crunch at home?

Crunch needs no equipment, so you can do it anywhere. Reverse crunch needs no equipment, so you can do it anywhere.

Which is easier on the joints, crunch or reverse crunch?

About the same: both rate Excellent for joint and recovery cost in our research rubric.