Originally Posted by T-Mar

They were called DH (Down Hill) bars because the inventor, Boone Lennon.had been a coach with the USA Alpine Ski Team and the handlebars put the cyclist in a "tuck" that resembled that of a downhill skier. The ski influence can also be seen in the shape of the arm rests, which are reminiscent of ski pole grips and it's been reported that the first arm rests were re-purposed ski pole grips,

The bars were originally marketed without the plastic nose bridge. However, it was soon discovered that adding this piece contributed substantially to the rigidity of the handlebar. The nose bridge was available as an aftermarket item starting in late 1988 but didn't come standard with the bars until 1990.