I run Highland Games at some of the Black Powder Rendezvous in the local area. Years ago I heard the "explanation" that the log was thrown to make a bridge during raids or battles. As has been posted earlier, I thought it was very unlikely. The best theory I've heard is that the event came about through logging. Men loading logs onto a cart let their competitive nature get the upper hand. I give a general explanation for the evolution of the Games, mentioning our penchant to make a contest of daily tasks, and the fact the Clan Chiefs looked for ways to determine their strongest and most agile men, so they knew who to keep near them in battle.