I have been a roadie for 7 yrs. now logging around 3-4 thousand miles a year. Two weeks ago my 11 yr. old son got me out mountain biking on a couple of real trails, one a snowmobile trail that went on forever, the other a barren rock cliff that surrounded a small lake in northern Ontario, (Muskoka). What a blast! This is a total body workout, every muscle in your body is used. The muscles in my legs are definatly strong enough for the short steep climbs but I found that my upper body needs a lot more strength to handle this type of riding, I will definatly do more of this to develop my upper body. After the ride you feel that you have done a "total" workout, unlike a road ride that concentrates mostly on your cardio, legs and arms. If you have never tried it and want a "total" body workout, do it, but do it on a real mountain bike trail with lots of climbs, descents, turns, and obstacles.
6 miles inland from the coast of Sussex, in the South East of England
Dale MT2000. Bianchi FS920 Kona Explosif. Giant TCR C. Boreas Ignis. Pinarello Fp Uno.
First mistake was you didn't knobble the 11 year olds bike. Second was agreeing to go out on his trails. Third mistake was finding out how hard it can be, and still enjoying it.
I can see another convert to wide knobblies in the offing.