For hamstring growth
For hamstring growth, stiff-leg 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.
Both are good choices, and they train the hamstrings 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. A 45° hip extension grew the long head of the biceps femoris more than Nordic curls did in a 10-week study.
Stiff-Leg Deadlift. Like the Romanian deadlift with straighter legs: a big hamstring stretch, with similar lower-back fatigue.
For hamstring growth, stiff-leg 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. Both are good choices, and they train the hamstrings 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 stiff-leg deadlift takes some practice.
45° back extension needs a GHD or back-extension bench, so for most people it’s a gym exercise. Stiff-leg 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 stiff-leg deadlift.