A bouncing ball problem


I have created a simple bouncing ball animation with nice arcs. Now my problem is with the timing and spacing. I know that i can change the timing with simply moving the keys. But how can i manage the spacing without changing the arcs so that i can achieve an easing in and out effect ? What pattern is used in blender for such problems?

This is achieved by adjusting the handles of your keyframes.
A standard technique is to set the handles of your up/down animation curve (usually Z position) so that your peaks to have auto clamped handles and your impacts to have vector handles. After that, manually adjust the handles so that the spacing looks right.