As a person is running, their soleus, gastrocnemius and tibialis anterior muscle

Question

As a person is running, their soleus, gastrocnemius and tibialis anterior muscles generate forces about their ankle joint. During late stance, the magnitudes of the forces are: soleus 1450 N and tibialis anterior 800 N. The magnitudes of the muscle moment arms about the ankle joint are: soleus 0.06 m, gastrocnemius 0.07 m, and tibialis anterior 0.04 m. What is the force generated by the gastrocnemius muscle if the net torque is -140 N m? What is the force generated by the gastrocnemius if the net torque is -70 N m? Gastrocnemius muscle force at net torque of -70 N m Gastrocnemius muscle force at net torque of -140 N m

Explanation / Answer

The force generated by Soleus at net torque would be force × moment that would be 1450 × 0.06 = 87 N m.

Whereas the force generated by tibialis anterior at net torque would be 800 × 0.04 = 32 N m.

Tibialis anterior imparts an antagonistic action on gastrocnemius muscles whereas Soleus imparts an agonist action, hence the net force generated would be

Net force = Force generated by tibialis anterior - (Force generated by soleus- Force of gastrocnemius)

-140 = 32 - (87+x)

-140 = 32 - 87 - x

-140 = -55 - x

hence -x = -140+55

hence force generated by gastrocnemius muscles would be 85 N m net torque.

The force would be 85/0.07 = 1214 N

If the net force is -70 N m then the force generated by gastrocnemius would be approximately 612 N.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.