Final answer:
True, both the gastrocnemius (fast-twitch) and soleus (slow-twitch) muscles are involved in plantar flexion with different fatigue resistance and speed of contraction. The largest muscle in the lower leg is the gastrocnemius.
Step-by-step explanation:
The statement 'The Gastrocnemius (fast twitch) & Soleus (slow twitch) muscles BOTH plantar flex the foot-the differences between them are the speed at which they cause this action & their ability to resist fatigue' is true. The gastrocnemius and soleus muscles are indeed responsible for plantar flexion of the foot. The gastrocnemius is the most superficial and visible muscle in the calf and is composed predominantly of fast-twitch muscle fibers, which contract quickly but fatigue more rapidly. On the other hand, the soleus is found deep to the gastrocnemius and is largely composed of slow-twitch muscle fibers, which are more resistant to fatigue and are efficient at maintaining posture and standing endurance.
Regarding the quiz question about the largest muscle in the lower leg, the correct answer is:
- b. gastrocnemius
While the soleus muscle is broad and powerful, the gastrocnemius is the largest and most superficial muscle of the calf that becomes visible when the calf is flexed.