You may specify to loop and/or change the speed of the special effects.
Move your mouse to the right edge of the SFX key bar. The cursor turns into a double-arrow.
Drag the cursor right. The bar starts to duplicate itself in order to loop.
Drag to loop for three times.
You may adjust the speed of the SFX through the modify page in the Special Effects panel by double-clicking on the SFX bar. Alternatively, you may adjust the speed on the timeline directly.
Move your cursor to the right edge of the SFX key bar. The cursor turns into a double-arrow.
Press and hold the Ctrl key.
Drag the cursor left or right to adjust the speed of the SFX. (Left: Accelerate; Right: Decelerate)
Decelerate the SFX
Accelerate the SFX