Yes! Mtn biking is a great opportunity to train your handling skills, improve your aerobic-anaerobic capacity and overall power, as well as having fun! When riding a mtn bike on dirt roads, one must be much more aware of your surroundings or you'll find yourself in trouble (usually on the ground!). The surface is different, unpredictable, rougher, ever changing, so you learn to ride with your eyes wide open and with a keener sense of your surroundings. You learn to work with your bike AND your body to handle the surface beneath you and the road ahead at the same time. Gravel, rocks, sand, dirt, mud all challenge the rider to maintain control, improve shifting techniques, turning and surging. In one ride you can train 3 energy systems! Your cornering is also improved because you learn to turn around tight, quick corners on unstable ground.
Now this might sound scary to some of you,(and it was to me being the rookie at mountain biking that I am!) but its mostly work and fun!! You can find beginner courses which make it mostly only fun at first, with little challenges. Mtn biking is great cross-training for the roadie and will really improve your fitness and road bike skills. Some of the best roadies came from mtn biking..i.e. Lance baby for one!!
So, get out there and ride :). There are different course levels of terrain out there and I suggest one begins on the "beginner" route to develop a feel for the mtn bike and the roads. Glory Hole does have some great courses at all different levels, as well as Bear Valley in the summertime! And theres more. Just ask your local bike shop and they should be able to provide some input for you.
because lifes a great ride.......