Hypertrophy: Hamstrings — Hip Hinge, Nordic Curls, and Training Science
Nordic curls produced 3× greater biceps femoris hypertrophy than lying leg curls in a 10-week study. Hip hinge exercises (RDLs) stretch hamstrings maximally; knee flexion exercises (leg curls) load the shortened position. Both movement patterns are required for complete hamstring development (Bourne et al., 2018 — PMID 29106500).
| Measure | Value | Unit | Notes |
|---|---|---|---|
| Nordic curl vs. lying leg curl: biceps femoris hypertrophy | 3× | greater with Nordic curl | Bourne 2018: Nordic curl produced 3× greater biceps femoris long head CSA increase than lying leg curl over 10 weeks |
| RDL vs. leg curl: hamstring stretch position | greater | stretch with RDL (hip hinge) | Hip hinge with knee extended maximally stretches all three hamstring muscles; leg curl loads knee flexion without full hip hinge stretch |
| Hamstring injury rate: Nordic curl-trained vs. control | 51 | % injury reduction | Bourne 2017 meta-analysis: Nordic curl training reduces hamstring strain injury rates by 51% in team sport athletes |
| Biceps femoris long head: primary injury-prone region | proximal myotendinous junction | most common strain site | 75% of hamstring strains occur at the proximal myotendinous junction of the biceps femoris long head — the Nordic curl targets this specifically |
| Lying leg curl: hamstring hip position | hip neutral (0°) | prevents full stretch | Hip neutral during lying leg curl prevents full hamstring stretch; hip flexed + knee extended is the only full stretch position |
| Optimal hip hinge depth for hamstring stretch | parallel to floor or below | torso angle | Torso parallel to floor with minimal knee bend (RDL) maximally lengthens hamstrings; maintain neutral spine throughout |
The hamstrings — comprising three muscles (biceps femoris long and short head, semimembranosus, semitendinosus) — perform knee flexion and, for the three biarticular muscles, hip extension. Their biarticular nature means full stretch requires simultaneous hip flexion and knee extension. This is a position not achieved by lying leg curls (hip neutral) and therefore requires hip hinge movements for complete hamstring development.
The most evidence-supported finding in hamstring training: Nordic curls produce 3× greater biceps femoris long head hypertrophy than lying leg curls at equivalent training volume (Bourne et al., 2018, PMID 29106500). This is a large magnitude effect, consistent with the stretch-mediated and eccentric overload mechanisms that make long-length training potent.
Hamstring Exercises: Comparison Table
| Exercise | Movement Pattern | Stretch Position | Biceps Femoris | Semimembranosus | Load Potential | Injury Prevention |
|---|---|---|---|---|---|---|
| Romanian deadlift (RDL) | Hip hinge | Maximum (hip flexed, knee extended) | High | High | Very high | Good |
| Nordic hamstring curl | Knee flexion + eccentric | Maximum (hip extended, knee bent) | Very high | Moderate | Bodyweight (eccentric) | Excellent |
| Stiff-leg deadlift | Hip hinge | Maximum | High | High | Very high | Good |
| Lying leg curl | Knee flexion | Minimal (hip neutral) | Moderate | Moderate | Moderate | Moderate |
| Seated leg curl | Knee flexion | Moderate (hip slightly flexed) | Moderate | Moderate | Moderate | Moderate |
| Good morning | Hip hinge | High | High | High | High (barbell) | Moderate |
| Single-leg RDL | Hip hinge (unilateral) | High | High | High | Moderate (dumbbell) | High (balance) |
| Cable pull-through | Hip hinge | High | High | High | Moderate | Good |
Nordic Curl: Mechanism and Programming
Bourne et al. (2018, PMID 29106500) compared Nordic curl vs. hip extension exercise training for 10 weeks in amateur soccer players. Nordic curl produced significantly greater biceps femoris long head CSA (+8.3% vs. +2.8%) and fascicle length increases (+12.4% vs. +6.4%). The longer fascicles from Nordic curl training provide greater injury resistance — shorter fascicles are a known injury risk factor.
The 51% hamstring injury reduction with Nordic curl training (Bourne 2017 meta-analysis, PMID 27294892) makes this exercise the highest injury-prevention-ROI exercise in team sports training. For non-athletes, the injury prevention benefit is lower but the hypertrophic benefit remains.
Seated vs. Lying Leg Curl
Seated leg curls (hip slightly flexed) produce slightly greater hamstring stretch than lying curls (hip neutral) and are preferred as the knee flexion exercise component of hamstring programming. Maeo et al. (2021, PMID 33105260) confirmed that training at longer muscle lengths (hip flexed during leg curl) produces greater hypertrophy than training at short lengths. This supports preferring seated over lying leg curls when both options are available.
Related Pages
Sources
- Bourne, M.N. et al. (2018). Impact of the Nordic hamstring and hip extension exercises on hamstring architecture and morphology. Medicine & Science in Sports & Exercise, 50(11), 2356–2364.
- Maeo, S. et al. (2021). Greater hamstrings muscle hypertrophy but similar damage protection after training at long versus short muscle lengths. Medicine & Science in Sports & Exercise, 53(4), 825–837.
- Bourne, M.N. et al. (2017). An evidence-based framework for strengthening exercises to prevent hamstring injury. Sports Medicine, 47(2), 251–267.
- Schoenfeld, B.J. (2021). Science and Development of Muscle Hypertrophy (2nd ed.). Human Kinetics.
Frequently Asked Questions
What is the best exercise for hamstring hypertrophy?
No single exercise is best — the hamstrings require both hip hinge (for stretch position loading) and knee flexion (for shortened position loading). Romanian deadlifts provide maximum stretch loading at the proximal hamstrings under heavy load. Nordic curls provide maximum eccentric overload at long muscle lengths (the most injury-susceptible position). Lying/seated leg curls add volume in the shortened position. A complete program combines all three movement types.
Why are Nordic curls so effective for hamstring development?
Nordic curls produce an eccentric contraction of the hamstrings at maximally lengthened position (hip flexed, knee extended) — precisely the mechanical scenario most potent for hypertrophy and injury resistance. Bourne et al. (2018, PMID 29106500) found 3× greater biceps femoris long head hypertrophy with Nordic curls vs. lying leg curls over 10 weeks. The combination of eccentric overload (body weight is high relative to hamstring strength) and long muscle length creates an uniquely potent stimulus.
Do RDLs replace leg curls for hamstring training?
No — they address different portions of the ROM and movement patterns. RDLs train the hip hinge pattern under heavy load with maximum stretch. Leg curls train the knee flexion pattern at varying hip positions. The biceps femoris long head (most injury-prone) is best developed by Nordic curls and RDLs specifically. The semimembranosus and semitendinosus benefit from knee flexion exercises. Hamstring completeness requires both patterns in programming.
How do you perform Nordic curls progressively?
Nordic curls are very demanding — most trainees cannot complete a full rep initially. Beginner progression: use a band or partner for assistance, lower slowly (3–5 second eccentric) and use arms to push up. Intermediate: unassisted slow eccentric (3–5s), controlled catch with hands, push up. Advanced: full eccentric + concentric. Nordic curl performance typically requires 4–8 weeks of consistent practice before full ROM reps are achievable. Once full reps are mastered, progression is through added reps and sets.