It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Companions complained to the Prophet (peace and blessings be upon him and his family) that if they spread out (in prostration), it becomes difficult for them in sujood. The Prophet (peace and blessings be upon him and his family) said: Then seek help from your knees. Ibn ‘Ajlan says: Its manner is that when the prostration becomes lengthy and a person becomes tired, he should rest his elbows on his knees.