For glute growth
For glute growth, the two are close. Romanian deadlift rates slightly higher: more stretch, easier to progress.
45° back extension is easier on the joints.
Both are good choices, and they train the glutes 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
45° Back Extension. Round the upper back slightly and the glutes take over.
Romanian Deadlift. Loads the glutes and hamstrings at the bottom of the hinge, where both are stretched. Heavy sets tax the lower back.
For hamstring growth, Romanian deadlift rates well ahead on our research criteria: more of the work on the hamstrings, more stretch. 45° back extension is easier on the joints.
For cycling, 45° back extension and Romanian deadlift score the same on every criterion.
For glute growth, the two are close. Romanian deadlift rates slightly higher: more stretch, easier to progress. 45° back extension is easier on the joints. Both are good choices, and they train the glutes 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.
45° back extension is easier: it’s easy to learn, while Romanian deadlift takes some practice.
45° back extension needs a GHD or back-extension bench, so for most people it’s a gym exercise. Romanian deadlift needs a barbell, so for most people it’s a gym exercise.
45° back extension: it rates Excellent for joint and recovery cost in our research rubric, against Good for Romanian deadlift.