Originally Posted by
tgbikes
About 25 yrs. ago, as I thought about geting a real bike I asked a friend (physical therapist) which hand position would be more comfortable. Her instant response was that the MTB ,horizontal pipe in front of you. was not a natural position. It requires many more muscles to maintane than the vertical palm position. Saying that you would never wake up with your hands in the MTB position. I'v wondered at the fortunes made, bar ends ,springey stems. ft. shocks, bar grips..
Mountain biking is very different than road/touring biking. The "attack position" puts you far further forward on the bike with your upper body with almost no weight on your hands, in a position to drive down on the hands to pump terrain or pull back and up to unweight the front. Its much more like doing push ups and deadlifts than it is sitting for hours and hours. Not that there aren't situations where you're chilling there for an hour long climb, but the bars are designed for aggressive riding. More modern bars are also much wider and more swept to enhance control while leaning the bike way over (rather than leaning with the bike), which a flat hand position allows much easier than a "neutral" hand position.
Tl;dr: mountain biking bars are designed for dynamic motion, not static comfort.