Rukoo' is a Fard action.
While releasing your hands from the position in Qiyaam, saying Allahu Akbar, bow down into Rukoo'.
Men - The arms are stretched to grasp and hold the knees firmly. The back should be as horizontally straight as possible.
Women - One puts the hands on the knees and bows only as much as required for the hands to reach the knees; holding the knees gently.
Whilst in Rukoo' recite the following 3 times:
سُبْحَانَ رَبِّیَ الْعَظِیْمِ
(Glorified is my Lord, the Most Great).
Immediately on completing the Rukoo' one should, saying Tasmee', rise back up standing upright in the position of Qawmah.
There are no Fard elements to Rukoo' rather it is an Pillar (Rukn) in itself.
To be motionless (stationary) in Rukoo' for the duration it takes to say Subhaan-Allah once.
To perform Rukoo' before Sujood.
To perform Rukoo' only once in a Raka'ah.
To stand up for Qawmah as soon as the Rukoo' has been completed (any pause should be less than it takes to recite Subhaan-Allah three times).
To say the Takbeer when going into Rukoo'.
To recite the Tasbeeh (glorification) سُبْحَانَ رَبِّیَ الْعَظِیْمِ three times.
Men:
- to keep the legs vertical and for back and head to be as straight as possible.
- to hold the knees firmly with the hands and to spread the fingers out.
Women:
- to bend only as much is necessary for the hands to reach the knees
- to hold the knees gently.