TAKEN-RACK SWAP · 100% MUSCLE OVERLAP

Machine Lying Leg Curl vs Nordic Curls

FR : Machine Lying Leg Curl ↔ Nordic Curls

Swapping Machine Lying Leg Curl (Machine) for Nordic Curls (Bodyweight) retains 100% overlap; expect alternative path. Compare exact 17-muscle fractional recruitment before swapping equipment mid-session.

Weighted Muscle Overlap
100%
Sum of min(coef A, coef B)
Primary Equipment
Machine → Bodyweight
Same rep/load measurement family
Load Transfer Protocol
Target RPE 7.5–8.5
Never assume 1:1 kg across leverages

Side-by-Side 17-Muscle Recruitment Delta

How primary mover (1.0× set) and synergist (0.5× set) allocation changes when swapping Machine Lying Leg Curl for Nordic Curls.

Muscle Group Machine Lying Leg Curl Nordic Curls Leverage Shift
Hamstrings Primary (85%) Primary (85%) Matched
Calves (Gastrocnemius & Soleus) Secondary (15%) Secondary (15%) Matched

Load & Volume Conversion: Machine Lying Leg Curl → Nordic Curls

Worked weight heuristic: a 115 kg set on Machine Lying Leg Curl (Machine) maps roughly to 70 kg on Nordic Curls (Bodyweight; 2.5 kg jumps, curve: alternative curve). Calibrate set 1 at RPE 8 so e1RM history for Machine Lying Leg Curl remains unskewed. Zero anatomical muscles are dropped between Machine Lying Leg Curl and Nordic Curls; 1:1 weekly set volume carries straight across.

Supporting Sports-Science Literature

Study Title Lead Author & Year Verified Link
Regional differences in muscle activation during hamstrings exercise. Schoenfeld (2015) PubMed 24978835 ↗
Fasting enhances mitochondrial efficiency in duckling skeletal muscle by acting on the substrate oxidation system. Roussel (2018) PubMed 29361595 ↗
Hamstrings Hypertrophy Is Specific to the Training Exercise: Nordic Hamstring versus Lengthened State Eccentric Training. Maeo (2024) PubMed 38857522 ↗
Robustness of hamstring muscle activation strategies following selective hypertrophy induced by Nordic hamstring curl and stiff-leg deadlift exercises. Morin (2025) PubMed 40586278 ↗

Related Biomechanical Swaps