I train obsessively - some of my friends think too obsessively - but hard training, if you focus on the right type of training sure does improve your climbing. Lately, I've been doing Crossfit work-outs. For a long time, I was a Mountain Athlete junkie but every single Mountain Athlete work-out is a beat down and, as I tend to take insufficient time off to recover, I was chronically tired and sore, and truthfully, not making any big strength or power gains.
Now, I'm Crossfitting three times a week, in addition to hill climbing (for time with a pack) and taking a rest day occasionally. I'm also continuing to work on my front lever, which is such an awesome core workout and a really good antidote to saggy bum climbing disease.
Saggy bum climbing disease is the epitome of climbing like you poo instead of like you screw. The bum hangs way down and out, the core is floppy, and the climber is inevitably pulling with the arms rather than pushing with the legs. Get rid of saggy bum climbing disease and your climbing grades will jump up immediately. Good exercises for combating saggy bum disease are knees to elbows or ankles to bar and front lever work.
What are you waiting for, grab a chin-up bar and get at it.
Hips into the rock, no saggy bum disease here