impact?

[stdtlj]

i dont know really if had to do an arc with my arm(inside_>outside ) or let naturally my arm down throug impact?
because when i saw books they speak about inside square inside
and i think i have to do an arc with my arms when i hit the ball
(because very often when i hit the ball i haven't got a consistent strike(sometimes vibtrations in my hands)i hit 3 perfect strike on 10

thank you for your answer

[GregJWillis]

You do not have to do an arc with the arms at all. You do the arc with the rotation of the body (Legs, hips and shoulders.) Just let the arms raise up and down.