Ibn al-Qayyim has summarized some of the acts which are permissible during the salah and which the Prophet sallallahu alehi wasallam used to perform at times. He writes:
The Prophet would pray and ‘Aishah would be lying between him and the qiblah. When he performed sajdah, he would signal to her with his hand and she would pull back her leg and when he would stand she would stretch out her leg again. The Prophet was praying and the Satan came to him to disturb his salah and the Prophet choked until his saliva came upon his hand. And the Prophet would pray upon the pulpit, making ruku’ there, but when the time came to perform sajdah, he would descend, moving backward, and prostrate upon the ground, and then return to the pulpit. He once prayed toward a wall and an animal tried to pass between him and the wall. The Prophet prevented the animal from passing to the extent that its stomach was against the wall. Once while he was praying, two girls from the tribe of ‘Abd al-Muttalib were fighting behind him and he separated them with his arms while he was praying. Ahmad’s version says that they grabbed unto his knees and he separated them without leaving the salah. On another occasion, when he was praying, a boy came to him and he motioned to him to move back, and he moved back. Then a girl tried to pass in front of him, he beckoned her to move back, but the girl passed, and when he finished, he said: “They are more determined.” Ahmad recorded it and it is also in the Sunan. He would also puff out air while praying. The hadith which states: “Puffing out is speech” cannot be traced to the Messenger of Allah, but Sa’id related it in his Sunan from Ibn ‘Abbas as one of Ibn ‘Abbas’ statements – if it is authentic. The Prophet would cry during his salah and would also clear his throat while praying. ‘Ali ibn Abi Talib said: “I had a certain time at which I would visit the Messenger of Allah. When I came to him, he would permit me to enter. If I found him praying, he would clear his throat and I would enter. If he was free, he would give me permission to enter.” This is recorded by an-Nasa’i and Ahmad. Ahmad’s version says: “I could enter upon the Prophet during the day or night. If I came to him while he was praying, he would clear his throat [as a sign that I may enter]. This was related by Ahmad who used to act by it and he was not of the opinion that clearing one’s throat invalidated the salah. Sometimes the Prophet would pray barefoot and sometimes while wearing shoes. This is what ‘Abdullah ibn ‘Umar said and he ordered people to pray with shoes on in order to differ from the Jews. Sometimes he would pray in one garment and sometimes in two garments and [this latter] was the majority of the cases.