And what is said regarding the limit of the completion of bowing and of keeping the back straight and the calmness with which it is performed.

Narrated Al-Bara:

The bowing, the prostration the sitting in between the two prostrations and the standing after the bowing of the Prophet (ﷺ) but not qiyam (standing in the prayer) and qu`ud (sitting in the prayer) used to be approximately equal (in duration).