Thoppu kārănām தோப்புக்கரணம்It is a form of yoga and done correctly would exercise all limbs and muscles. Beneficial more to head and temple region. The knocks on sides of temples sure to act a la acupuncture as trigger to activate nodes that are in communication with left & right hemisphere of the brain. Hindus especially orthodox begins their pooja with this exercise simultaneously chanting prayer to Lord Vinayaka aka Ganesha. My dad as soon as he finishes with morning debts, would apply sacred ash generously on his forehead and begin this thoppukaranam with prayer to Lord Ganesh followed by chanting and sandhyavandanam. Naughty students in my school days in class-rooms often gets punished with performing this exercise thoppukaranam. It used to be 108 times. It is performed hugely more number of times before annual exams at temples . Here in video below a doctor explains benefit of doing thoppu karanam to a man in Europe.