For glute growth
For glute growth, the two are close. Smith machine hip thrust rates slightly higher: more of the work on the glutes, easier to progress.
45° back extension gives more stretch.
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.
Smith Machine Hip Thrust. A hip thrust on rails: stable and simple to load, with the glutes working mostly at the top.
For glute growth, the two are close. Smith machine hip thrust rates slightly higher: more of the work on the glutes, easier to progress. 45° back extension gives more stretch. 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. Smith machine hip thrust needs a Smith machine and a bench, so for most people it’s a gym exercise.
About the same: both rate Excellent for joint and recovery cost in our research rubric.