背せが伸のびる

expression, ichidan verb

grow taller; increase in height

Used specifically for people getting taller, often children or teenagers. The subject is the person, not the height itself.

• 最さい近きん、息子むすこの背せが伸のびて、服ふくが小ちいさくなった。

  Recently my son has grown taller and his clothes have become too small.

• 中ちゅう学がく生せいのとき、一いち年ねんで背せが10センチ伸のびた。

  When I was in junior high, I grew 10 centimeters in one year.