For glute growth
For glute growth, the two are close. 45° back extension rates slightly higher: more stretch.
Glute kickback machine is easier to progress.
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.
Glute Kickback Machine. Isolates one glute at a time on a fixed path. Simple to load and easy to recover from.
For glute growth, the two are close. 45° back extension rates slightly higher: more stretch. Glute kickback machine is easier to progress. 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.
About the same: both are easy to learn.
45° back extension needs a GHD or back-extension bench, so for most people it’s a gym exercise. Glute kickback machine needs a machine, so for most people it’s a gym exercise.
About the same: both rate Excellent for joint and recovery cost in our research rubric.