Work of legs before the second topspin

Hello Alois and Jeff,

If i do a topspin off backspin, my legs are low at the starting position. And then i often have to do a smash or a topspin of a block, and at this point, i would like to know how is the right position of my legs just before to do the second stroke. Do i have to stand up or not, and if yes, when ? (before or during the stroke).

My opponents often say that if they can return the first topspin, they don't have problem anymore. That means that the fifth ball (for me) is not good enough, and this is probably due to a bad moving to a right starting position.

Could you tell or show me how the legs have to move between this two strokes ?

Thank you in advance and for all you do. This is wonderful.

Christian