In some quick googling around, the biggest issues I could find included:
- Hunched shoulders -- suggesting upper back or general posterior chain weakness
- Difficulty of spreading fingers -- the opposite of a grip problem, manifests itself as inflammation pain in the fingers.
The hunched shoulders I think are the more common issue that plagues a number of sports, not just climbing or bouldering. The good news is most of this can be addressed with common barbells and dumbbells. You might even get away with some body weight only exercises.
Fixing Hunched Shoulders
This comes from pulling yourself up while facing the rock, particularly if you don't hold yourself close to the face of the rock. It seems contradictory that a sport dedicated to pulling yourself up can result in hunched shoulders. One cause can be allowing your shoulders to shrug forward during "rests". You can see that when strongmen are pushing themselves on their farmers walks. The chest compensates to keep the shoulders in their sockets, which means more force pulling the shoulders forward. If you have gotten to a state where you are shrugging forward all the time, it's because you lack sufficient strength in the upper thoracic portion to keep the shoulders back even when you are relaxed.
Common exercises that can address this are:
- Dumbbell reverse flies (targets the rhomboids and posterior deltoids)
- Dumbbell front raises (targets the lats and rotator cuff)
- Back extentions, rounded (targets the entire back, round at the bottom and raise up with the shoulders first ending in a sort of superman position)
- Squats (hits the entire posterior chain, and strengthens your entire core)
- Deadlifts (also hits the entire posterior chain and strengthens your entire core)
- Any type of row (hits the upper back)
If you already have pronounced hunchback going on, I would start with the the following:
- rounded back extentions body weight only 3x8-10.
- dumbbell work (both listed above) at light weight for 5x20.
- rows as heavy as you can and still pinch your shoulder blades together 3x8-10
The dumbbell work would be every time, and alternate the back extensions and rows. After that, squats and deadlifts will be awesome to build general strength and keep everything good.
Finger inflammation
The most common cause for a joint becomes inflamed is when you keep using it one way, and don't balance that work going the other way. For example, bench pressers who don't do any curls or pull ups tend to have inflammation in the elbows. Cyclists and runners who don't do anything for their hamstrings or posterior chain can have problems with their knees. The same goes for gripping small crevasses to support your whole body weight.
The good news is you don't have to balance the intensity of the work to get good results. You just need to get blood flowing through the joint with very high rep work (5x20, or any variation of 100 reps total).
To address the finger inflammation, use a rubber band around your fingers and open your hand enough to work against the resistance, but not so much that the rubber band rolls up on your hand.