For hamstring growth

45° Back Extension vs Seated Leg Curl

For hamstring growth, seated leg curl 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)

Research score

Target tension

Good

Excellent

Loaded stretch

Strong

Excellent

Progression

Strong

Excellent

Low cost

Excellent

Strong

See the full hamstrings ranking

What these mean

Target tension.: Whether the muscle you’re training is what gives out first, not your grip, balance or other muscles.
Loaded stretch.: How hard the muscle works while stretched. Training it there is linked to more growth.
Progression.: How easily you can keep adding weight in small steps over months and years.
Low cost.: How easy it is on your joints and recovery, and how quickly you can learn it.

The research score comes from these, scored by hand from the studies. Lifter scores appear once an exercise has 10 ratings. How scores work

When each one fits

Good reasons to choose 45° back extension

You want something easier on your joints
You want to train more muscles at once

Good reasons to choose seated leg curl

You want the hamstrings to do the work, not other muscles
You want more load on the hamstrings while they’re stretched
You want to keep adding weight in small steps

45° Back Extension

Seated Leg Curl

You need

GHD / back-extension bench

Machine

Skill

Easy to learn

Type

Compound

Isolation

Why they rank where they do

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.

Seated Leg Curl. Seated curls grew the hamstrings more than lying curls (+14% vs +9%) in a 12-week study.

From the research

Bourne et al., 2017: Both exercises lengthened the biceps femoris fascicles and grew the semitendinosus; 45° hip extensions grew the biceps femoris long head more than Nordics. (30 recreational male athletes; 10 weeks.)Cited for 45° back extension in hamstrings
Maeo et al., 2021: Seated leg curls grew the hamstrings more than lying leg curls (+14% vs +9% volume) over 12 weeks. (20 untrained adults; one study.)Cited for seated leg curl in hamstrings

Questions

Which is better for hamstring growth, 45° back extension or seated leg curl?

For hamstring growth, seated leg curl 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.

Is 45° back extension or seated leg curl easier to learn?

About the same: both are easy to learn.

Can you do 45° back extension or seated leg curl at home?

45° back extension needs a GHD or back-extension bench, so for most people it’s a gym exercise. Seated leg curl needs a machine, so for most people it’s a gym exercise.

Which is easier on the joints, 45° back extension or seated leg curl?

45° back extension: it rates Excellent for joint and recovery cost in our research rubric, against Strong for seated leg curl.

More comparisons

45° Back Extension Seated Leg Curl All hamstrings exercises

45° Back Extension vs Seated Leg Curl

For hamstring growth, seated leg curl rates well ahead on our research criteria: more of the work on the hamstrings, more stretch.

45° back extension is easier on the joints.

What these mean

Target tension.: Whether the muscle you’re training is what gives out first, not your grip, balance or other muscles.
Loaded stretch.: How hard the muscle works while stretched. Training it there is linked to more growth.
Progression.: How easily you can keep adding weight in small steps over months and years.
Low cost.: How easy it is on your joints and recovery, and how quickly you can learn it.

The research score comes from these, scored by hand from the studies. Lifter scores appear once an exercise has 10 ratings. How scores work

When each one fits

Good reasons to choose 45° back extension

You want something easier on your joints
You want to train more muscles at once

Good reasons to choose seated leg curl

You want the hamstrings to do the work, not other muscles
You want more load on the hamstrings while they’re stretched
You want to keep adding weight in small steps

45° Back Extension

Seated Leg Curl

You need

GHD / back-extension bench

Machine

Skill

Easy to learn

Type

Compound

Isolation

Why they rank where they do

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.

Seated Leg Curl. Seated curls grew the hamstrings more than lying curls (+14% vs +9%) in a 12-week study.

From the research

Bourne et al., 2017: Both exercises lengthened the biceps femoris fascicles and grew the semitendinosus; 45° hip extensions grew the biceps femoris long head more than Nordics. (30 recreational male athletes; 10 weeks.)Cited for 45° back extension in hamstrings
Maeo et al., 2021: Seated leg curls grew the hamstrings more than lying leg curls (+14% vs +9% volume) over 12 weeks. (20 untrained adults; one study.)Cited for seated leg curl in hamstrings

Questions

Which is better for hamstring growth, 45° back extension or seated leg curl?

Is 45° back extension or seated leg curl easier to learn?

About the same: both are easy to learn.

Can you do 45° back extension or seated leg curl at home?

45° back extension needs a GHD or back-extension bench, so for most people it’s a gym exercise. Seated leg curl needs a machine, so for most people it’s a gym exercise.

Which is easier on the joints, 45° back extension or seated leg curl?

45° back extension: it rates Excellent for joint and recovery cost in our research rubric, against Strong for seated leg curl.