I was paging through one of Peter Alliss' many books recently, one published in the early 1980s. Writing about a golfer named Count John de Bendern (a k a, John de Forrest, the name under which he won the 1932 British Amateur Championship), Alliss said this:
"He was a somewhat eccentric player, an extreme oddity of his play being the condition known as 'choking,' in which the afflicted player cannot take the club away from the ball, but waggles the clubhead to and fro an eternity, or remains rigidly immobile."
In Alliss' vocabulary of the early 1980s, choking was used sparingly enough that it required quotation marks. And the meaning is different. What Alliss describes is, indeed, a loss of nerve, but one that results in a constant waggling or re-gripping of the type from which Sergio Garcia suffered several years back. Today we might be more likely to refer to this as the full-swing yips, or yipping ones irons. We wouldn't call it choking.
But Alliss' words do provide a clue from where the term choking comes. If that example - the inability to pull the trigger on a shot resulting in interminable waggling - was the common meaning at one time, then the term "choking" probably originated in golf as a reference to "choking up" or "choking down" on the club grip. The readjusting of ones hands on the grip during the waggling. Ala Sergio's troubles.
Alliss also included a funny story about Count de Bendern. At The Masters one year, his ball found water on the 13th hole. De Forrest could play the ball by putting one foot into the water, with one foot on the bank out of the water. So he removed one shoe and one sock, and then stuck the foot on which he'd kept on his shoe into water.