Joseph wrestles with William Wall, the best wrestler in Ramus, and throws him. That evening he blesses 19 children and records, "Virtue went out of me, and my strength left me, when I gave up the meeting to the brethren." The next day he explains the reason for this virtue going out of him. He states that he saw the influence of Lucifer and strove with all his might to protect the children against it. For this reason he becomes weak and has still not recovered by the next day.
[Source: Conkling, Christopher J., Joseph Smith Chronology]