For your abs
For your abs, machine crunch rates well ahead on our research criteria: easier to progress, easier on the joints.
Ab wheel rollout gives more stretch.
Both are good choices, and they train the abs differently. Using both across your week covers more of the muscle than either alone: in studies, varied exercises grew parts of a muscle that one exercise missed. (Fonseca et al., 2014; Costa et al., 2021)
The research score comes from these, scored by hand from the studies. Lifter scores appear once an exercise has 10 ratings. How scores work
Ab Wheel Rollout. Hard work for the abs in a stretched position, but difficult to progress and tough on the lower back if form slips.
Machine Crunch. Loaded spinal flexion on a fixed path, easy to progress like any other machine.
For your abs, machine crunch rates well ahead on our research criteria: easier to progress, easier on the joints. Ab wheel rollout gives more stretch. Both are good choices, and they train the abs differently. Using both across your week covers more of the muscle than either alone: in studies, varied exercises grew parts of a muscle that one exercise missed.
Machine crunch is easier: it’s easy to learn, while ab wheel rollout takes some practice.
Ab wheel rollout needs no equipment, so you can do it anywhere. Machine crunch needs a machine, so for most people it’s a gym exercise.
Machine crunch: it rates Excellent for joint and recovery cost in our research rubric, against Good for ab wheel rollout.