Train your feet to move as fast as your hands in the air. You need to strengthen your waist and thigh as well.
10 seconds sound clip from the The Woman Avenger (1980) movie soundboard.
You can hear this line at 01:08:32 in the DVD version of the movie.
Quote context
[...]
- You must develop the ability to kick fast.
- The Ox tendon is strongest. Push your legs against it as far as you can. Keep practicing.
- But most important, you must be able to stretch your legs in any direction.
- Oh sister! My legs, I can't stand it!
- You must learn to stand it, if you still want to get your revenge.
- Up further. Try to use the strength for your entire body.
- Hold this water bag, you need to strengthen your body more.
[...]