For hamstring growth
For hamstring growth, the two are close. 45° back extension rates slightly higher: easier to progress, easier on the joints.
Nordic curl keeps more of the work on the hamstrings.
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.
Nordic Curl. A brutal eccentric. Great for resilience; hard to progress for growth.
For hamstring growth, the two are close. 45° back extension rates slightly higher: easier to progress, easier on the joints. Nordic curl keeps more of the work on the hamstrings. 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 Nordic curl takes some practice.
45° back extension needs a GHD or back-extension bench, so for most people it’s a gym exercise. Nordic curl needs no equipment, so you can do it anywhere.
45° back extension: it rates Excellent for joint and recovery cost in our research rubric, against Good for Nordic curl.