The Curious Phenomenon of the Jumping Lumberjacks

In 1878, the American Neurological Association was informed of a strange phenomena in the lumber camps of northern Maine. A visit to the camps proved the stories to be true. Many of the lumberjacks and their family members were extremely sensitive to being startled, and they reacted by jumping to extreme heights. Not only that, but they would unthinkingly and immediately obey any command given to them during the startle. Those afflicted became known as "the Jumping Frenchmen of Maine," since many of them were of French-Canadian heritage. 

Later studies proved that the condition was not limited to any ethnicity, nor to the state of Maine. Experts thought it might be genetic, but it only appeared that way because the affected logging camps contained families. At first you might think the jumping reflex might be related to the dancing manias of medieval Europe, but then it also seems akin to the physical condition that affects the fainting goats of Tennessee. Then in the 1960s, yet another possible cause arose from sociological studies in isolated lumber communities. We still don't know the exact cause of the jumping syndrome because it doesn't happen anymore, but you can read what we do know about it at Amusing Planet.