"Be moderate in bowing and prostration, and do not rest your forearms along the ground like a dog."  

عَنْ رَسُولِ اللَّهِ ﷺ قَالَ اعْتَدِلُوا فِي الرُّكُوعِ وَالسُّجُودِ وَلاَ يَبْسُطْ أَحَدُكُمْ ذِرَاعَيْهِ كَالْكَلْبِ