A four-character idiom meaning to put one's heart and soul into every pitch (or action); used literally in baseball and figuratively to mean giving full effort to each attempt.
彼は常に一球入魂の精神でマウンドに立っている。
He always stands on the mound with the spirit of putting his heart into every pitch.
プレゼンでも一球入魂の気持ちで準備した。
I prepared for the presentation with the mindset of giving it my all.
監督は選手たちに一球入魂を求めた。
The coach demanded that the players give their all for every pitch.