Is Jalsat al-Istiraha sunnah?

Q: Is it recommended to make jalsat al-istiraha before standing in prayer?

A: Jalsat al-Istiraha is when the one praying sits after the second prostration in every rak'ah that is proceeded with standing e.g. the first and third in a four rak'ah prayer and resembles the sitting which is done between the first and second prostrations. This sitting is meant to provide a short period of rest for the one praying as if they have become fatigued.

This sitting is not recommended and should only be done if needed. What is recommended is for one to get up immediately after prostration, placing their hands on their knees to support their weight or the ground if they are weak.

ٍSource: Kashshaf al-Qinaa', al-Insaf, Matalib Uli al-Nuha