It's not going to be a backscatter event if your ping-pong ball hits the frame or these strings, or the top part.

打到原子核了就是背散射,如果打到框上。

麻省理工公开课 - 化学原理课程节选

It's a little easier to hit the ball hard to the opposite side from the side which is your foot and that's the same principle in baseball.

从另一侧击球更容易发力,在棒球中这个道理也是适用的

耶鲁公开课 - 博弈论课程节选