Wrong answer, elastic band probably....... ^_^

hi, friend! I have been learning this style for one year now. At the very beginning it is normal, but please be advised, you should practice it from relaxed movement, don't exert force from arms, try to use your core!!! That was the first. Second, after practice, we all have red and a little bit swollen hands. Then, stand straight, raise your hands (spread fingers, arms and fingers point to the sky) and shake your whole body like a wave (preferred from the knees to the fingers). Third, as a martial art, from my point of view, you are recommended to practice under a very experienced teacher!!! This is not like DIY tools, that can be done through youtube, if you damage or destroy the material, you can find a new one. But, you practice in a wrong way, you may suffer from the body damage in some serious situation. However, if you are unable to find a teacher and learn it on youtube, I hope you do it very slowly and gradually increase the speed. Anyway, just be very careful when practicing it or any other martial arts without teachers. I hope my suggestion is helpful and I genuinely wish you enjoy your practice.^_^

I doubt it’s a combat application, probably just meant to condition the hands to be stronger and more capable of handling blood pressure build up from swinging punches.