Straight Knee vs. Bent Knee: Two Calf Raises, Two Muscles
Why knee position changes which calf muscle a calf raise emphasizes.
Before this: The Lower Legs: An Overview
You will be able to
- Explain why a straight-knee calf raise emphasizes the gastrocnemius.
- Explain why a bent-knee calf raise emphasizes the soleus.
- Identify the tibialis anterior exercise that balances calf-focused training.
A joint-crossing difference
The gastrocnemius crosses both the knee and the ankle; the soleus crosses only the ankle. A muscle that crosses a joint is most effective when it is lengthened across that joint — so:
- A standing calf raise (knee straight) lengthens the gastrocnemius across the knee, emphasizing it.
- A seated calf raise (knee bent) slackens the gastrocnemius, shifting emphasis to the soleus.
Balancing with dorsiflexion
Both calf raises train plantarflexion. Adding a tibialis toe raise trains the opposing dorsiflexion action, giving the lower leg balanced strength in both directions at the ankle — useful for walking/ running mechanics and general ankle health.
Sources for this lesson
“The gastrocnemius crosses the knee and ankle while the soleus crosses only the ankle, changing which is emphasized by knee position.”
Anatomy and Physiology 2e — OpenStax, Rice University · Ch. 11.6 Appendicular Muscles of the Pelvic Girdle and Lower Limbs
Peer-reviewed textbook · License: CC BY-NC-SA 4.0 · Last checked 2026-07-19
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