Sahl bin Sa'd (may Allah be pleased with him) narrates that the Companions (may Allah be pleased with them) used to pray with the Messenger of Allah (peace and blessings be upon him) with their waist-wrappers tied around their necks because they were small, and the women were told: "Do not raise your heads in the prayer until the men have sat up straight."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3300