I ride with a lot of different riders and ride all woods tight trail riding. I have noticed that if your doing any type of racing, your conditioning boils down to how often your ride and how many miles you put on your bike between races. My rides in the good season range from 70 to 200 miles per day 3 to 4 days a week. I have never raced but know that when I ride with people that race that don't ride much between races that; They may be faster than me but can only last half the day. Try going out more often and intended to put some serious miles on your bike. There is no better way to work out for riding than riding a lot. Trail maintenance is another great one. Go ride 70 miles and buck logs off the trail all day.
As much as I value technology on a daily basis I believe the more you give you self to do while riding (worrying about heart rate and such) the less you are paying attention to riding skills. Know that if you ride hard you are pumping the crap out of your heart and it has not exploded yet right. Hehehehe, Hanging on to a motorcycle in the woods or on a track for 50 plus miles three days a week is by far a better, harder, and much more fun workout that sitting in a gym.
Sorry, I'm just gymophobic as I refuse to be part of the ratt race and the only indoor exercise I will be doing is my girlfriend or a 12 ounce curl. Hahahahahaha!
I like this guy! He speaks gospel! I can't fault a word he said!