Lying leg curl
Machine
Primary muscles
Secondary muscles
Isolates the knee-flexion role of the hamstrings. The gastrocnemius assists because it also crosses the knee.
Form cues
- Hips stay down on the pad
- Curl the heels toward the glutes
- Lower slowly
Machine
Isolates the knee-flexion role of the hamstrings. The gastrocnemius assists because it also crosses the knee.
| Muscle | Role | Action |
|---|---|---|
| Hamstrings | Primary | Flex the knee and extend the hip |
| Gastrocnemius | Secondary | Plantarflexes the ankle and flexes the knee |
| Sartorius | Secondary | Flexes, abducts and laterally rotates the hip; flexes the knee |
Primary muscles are the prime movers; secondary muscles assist or stabilise. The balance shifts with grip, stance, range of motion and technique.