YOU SAID:

If I kicked a rock around the world, then it would hit me in the back of the head.

INTO JAPANESE

私が世界中の岩を蹴ったなら、それは頭の後ろで私を打つだろう。

BACK INTO ENGLISH

If I kicked the rocks around the world, it would strike me behind my head.

INTO JAPANESE

私が世界中の岩を蹴ったなら、それは私の頭の後ろで私を襲うだろう。

BACK INTO ENGLISH

If I kicked the rocks around the world, it would strike me behind my head.