YOU SAID:

Expand your chest, and avoid rounding your back!

INTO JAPANESE

胸を広げて、背中を丸めないようにしましょう!

BACK INTO ENGLISH

Spread your chest wide and don't curl up on your back!

INTO JAPANESE

胸を大きく広げて、背中に丸まらないでください!

BACK INTO ENGLISH

Spread your chest wide and don't curl up on your back!