Musannaf Ibn Abi Shayba 1:798

Waki’ narrated to us, from Usama bin Zayd, from al-Maqburi, from Umm Salama, that she asked the Prophet (may Allah bless him and grant him peace): "I am a woman who braids her hair tightly, so what should I do when I perform ghusl?" He said: "Pour three handfuls of water over your head, then press (or rub) after each handful."