This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
[{'content': 'Which of the following muscle is used in normal walk during stance and swing? \nSelect and explain. \nA. Popliteus, B. Gastrocnemius, C. Tibialis anterior, D. Iliopsoas', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Normal walking constitute of stance phase (when at least one leg is in contact with the ground) and swing phase (when the leg is in air). Together, the soleus, gastrocnemius, and plantaris act as powerful plantar flexors of the ankle joint. They provide the main forward propulsive force in walking and running by using the foot as a lever and raising the heel off the ground. Ref: Clinical Anatomy By Regions By Richard S. Snell, 2011, Page 487.', 'role': 'assistant'}]