You should try that motion 10 times(10 kicks) at a set, and try 3 sets at first.
And then, you should increase the number your repetition.
Very hard training.
But good to increase power and to reform of your kicking pose.

You should not sit down completely when you finished each kick. I mean, you should not bent your knees completely. It can injure your knees and another part of your legs.