expression, godan verb (-ru)
put one's heart into; be absorbed in; give one's all
Used when someone becomes fully engaged or absorbed in an activity, often with a sense of enthusiasm or dedication. Commonly appears in negative form 身が入らない to express lack of focus.
最近、仕事に身が入らない。
Lately, I can't get into my work.
彼は練習に身が入っている。
He is putting his heart into practice.