Physical benefits of prayer postures
 

I was listening to a lecture and this aspect was raised. Salaah is little like "spiritual yoga or pilates".

Qiyam (standing): I can't see any benefit apart from standing "straight" which would assist general posture.

Ruku' (bowing): a nice back stretch exercise! Keeping the back straight is important. Aids flexibility and suppleness. Good for the hamstrings.

Sujood (prostration): blood runs to the head / brain helping it? Inverter machines do a similar job.

Tashahhud (kneeling): my knees and ankles sometimes "click" in this position. Dont know of any benefit. In everyday life you normally don't sit in this position.