question #1 Sahih Muslim 474a, Book 4, Hadith 224 : What does this narration indicate about the practice of following the Imam in prayer?

They used to say prayer behind the Messenger of Allah (ﷺ). I never saw anyone bending his back at the time when he (the Holy Prophet) raised his head, till the Messenger of Allah (ﷺ) placed his forehead on the ground. They then fell in prostration after him.