1, direction: bend the root from the knee and scrape down, only scraping in one direction at a time, not scraping back and forth like bathing! If you have varicose veins or edema of lower limbs, you must scrape from bottom to top to improve blood circulation, otherwise the opposite direction will become more and more serious. If not, both directions are ok, but of course it is better to go down, which will relax tired legs and improve blood circulation.
2, strength: must be strong, scraping fast!
(Of course, the harder the better, the more tolerant you are. As long as you insist on scraping, it will have an effect. )