It was the day of Preparation, and the next day was a High Sabbath. In order that the bodies would not remain on the cross during the Sabbath, the Jews asked Pilate to have the legs broken and the bodies removed.
KJV
The Jews therefore, because it was the preparation, that the bodies should not remain upon the cross on the sabbath day, (for that sabbath day was an high day,) besought Pilate that their legs might be broken, and [that] they might be taken away.
ASV
The Jews therefore, because it was the Preparation, that the bodies should not remain on the cross upon the sabbath (for the day of that sabbath was a high day), asked of Pilate that their legs might be broken, and that they might be taken away.