Exercise is good for the development of one's body.
Exercising really helps develop your muscles and it's also good for your overall physical health.
この場合、次のような言い方ができますよ。
ーExercise is good for the development of one's body.
「運動は体の発達に良い」
もう少し詳しく言うとより自然な感じになります。
ーExercising really helps develop your muscles and it's also good for your overall physical health.
「運動は筋肉の発育を助け、健康全体にも良い」
ご参考まで！
カナダ 
