For biceps growth
For biceps growth, the two are close. EZ-bar curl rates slightly higher: easier on the joints, easier to progress.
Preacher curl gives more stretch.
Both are good choices that train the biceps the same way, so they swap freely. Rotating between them every few weeks is an easy way to vary your training.
The research score comes from these, scored by hand from the studies. Lifter scores appear once an exercise has 10 ratings. How scores work
EZ-Bar Curl. Heavy, simple biceps loading with a grip kinder to the wrists than a straight bar. Little stretch at the bottom.
Preacher Curl. Big stretch, but bouncing out of the bottom is where elbows get tweaked.
For biceps growth, the two are close. EZ-bar curl rates slightly higher: easier on the joints, easier to progress. Preacher curl gives more stretch. Both are good choices that train the biceps the same way, so they swap freely. Rotating between them every few weeks is an easy way to vary your training.
About the same: both are easy to learn.
EZ-bar curl needs an EZ bar, so for most people it’s a gym exercise. Preacher curl needs an EZ bar and a bench, so for most people it’s a gym exercise.
EZ-bar curl: it rates Excellent for joint and recovery cost in our research rubric, against Good for preacher curl.