Gastrocnemius
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A 2-joint calf muscle that plantar-flexes the ankle and flexes the knee; origin at the femoral condyles, insertion at the calcaneus.
Detail
The gastrocnemius originates at the posterior surfaces of the two condyles of the femur and inserts at the posterior surface of the calcaneus (Thompson, 1989). Its functions are plantar flexion of the ankle and flexion at the knee (leg curl). The exercise is standing calf raises — this powerful muscle becomes ineffective when the knee is flexed (check the origin), so the knees must be straight or nearly so. It has 2 heads, and one head can be emphasized over the other. To reduce gastrocnemius involvement in hamstring leg curls, keep it in plantar flexion.
Key facts
- 2-joint muscle: plantar flexes the ankle and flexes the knee.
- Origin: posterior surfaces of the two femoral condyles; insertion: posterior surface of the calcaneus.
- Becomes ineffective when the knee is flexed — keep knees straight/nearly straight for standing calf raises.
- Has 2 heads; one head can be emphasized over the other.
Connections
- Calves (Gastrocnemius and Soleus) — calf group.
- Soleus — the other calf muscle.
- Plantar Flexion — primary movement.
- Two-Joint (2-Joint) Muscles — 2-joint behavior.
- Standing Calf Raises — training exercise.
Sources
Exercise guides
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Educational content only — not medical advice. Always consult a qualified professional for individualized guidance, especially around injury, pregnancy, or medical conditions.