I've been really overwhelmed with the response to this site and my inbox is flooded with questions and ideas from you. Thanks! I will get round to answering them all and posting up the articles you've asked for, but I've had a great many so please bear with me!
"For a long time now I have been questioning the effectiveness of training finger strength through traditional training techniques like deadhangs, finger board workouts, etc. All these exercises rely on applying weight to a static hand position, crimping for instance, until failure. But how effective are static isometric contractions for training strength? Other resources on general strength training I have read reject this type of training because it is relatively ineffective compared to engaging the muscle over a range of movement. If I were going to train my chest muscles, I would never just hold the bench press bar in a static position until I was tired. I can't figure out why exactly we train our fingers and forearm muscles this way. The flip side to my thinking is that climbing basically involves a series of isometric finger contractions to get up a route, so is this training simply sport specific, therefore effective?"
Connor has really answered his own question at the end. This comes down to the basic principle of specificity - you get good at what you do. Most sports require using a muscle through a proportion, or all of its range of movement and in a dynamic (moving) contraction rather than isometric. So mimicking this in training is needed. But with climbing we hang isometrically (isometric means the muscle is producing tension but not contracting - i.e our fingers stay still on the holds) from holds so must do this in training too. Of course we use different muscle lengths in the different grips (crimp, openhand etc) so this also has to be done in training because the carryover of strength at one muscle length is limited at another. So stick to the hangboards!
Isometric contraction is actually surprisingly rare in sport. Endurance of isometric contractions, or more specifically, intermittent isometric contractions in the case of climbing is very interesting from a physiological point of view because of the effect of the high intramuscular pressure on blood flow inside the muscle. There is some interesting research on this in the fields of dingy sailing (yes I know, I was surprised too!) and motocross (also a forearm fatigue issue in this sport). More on this later...