Elder Joseph B. Wirthlin, a member of the Quorum of the Twelve of The Church of Jesus Christ of Latter-day Saints, suffered from a case of locked knees during his talk last weekend at the 177th Semiannual General Conference in the Conference Center.

According to Elder Wirthlin's son, Joseph B. Wirthlin Jr., his father "basically locked his knees and had his muscles twitching."

During his Saturday afternoon address on "The Great Commandment," Elder Wirthlin, 90, started to shake. Soon a colleague, Elder Russell M. Nelson of the Twelve, helped brace him with one hand from the back.

Although still shaking, Elder Wirthlin was able to finish his talk in its entirety, with the assistance of Elder Nelson.

"He didn't fall down," Wirthlin Jr. said. "He's as healthy as a 90-year-old can be."

A statement from the LDS Church's Public Affairs Office said Elder Wirthlin attended all five sessions of General Conference and continues this week, as usual, in his daily church assignments.

Joseph Wirthlin Jr. also said he likens the locked knees experience to anyone trying to hold up a weight in the air. After a while, your arms start to shake, as your strength fades.

Elder Wirthlin has no health problems, other than old age. His blood pressure and all other functions are good, his son said. "He keeps a fairly full schedule."

Elder Wirthlin is the oldest apostle and the second-oldest, behind President Gordon B. Hinckley, in the church's top administrative bodies.

Born on June 11, 1917, he was ordained an apostle on Oct. 9, 1986, at the age of 69. He was sustained as an assistant to the Twelve on April 4, 1975, and to the First Quorum of Seventy on Oct. 1, 1976.