Thanks for all the questions on training. I can't answer all of these but will try to give answers when they are repetitive. I have gotten many questions on athletes who keep getting injured from plyometrics.
I want to be clear on any type of program you follow. If you are trying to become a World class athlete in distance running. The number one rule is to be healthy and be able to train at high levels of volume and build two bases for the body both in specific muscular strength and aerobic strength. The goal being able to recover from high workloads of Specific endurance. You must be able to train consistent for many years both in volume and at levels that stimulate your aerobic systems and nervous sytem to aid specific endurance.
1. How to develop specific muscular strength?- To keep you healthy and aid Specific endurance. With many ways to develop specific strength so that individual fibers are stronger and recover from training it becomes imperative that this base does not interfere with the main goal of absorbing the training that matters. (RUNNING) That is aerobic running that supports specific endurance. So with so many ways to strengthen your body, weights, Plyometrics, Hills, it becomes not super important which you use but which can keep you healthy and aid your development not take away. I personally like Hills drills and core because the goal is to be a stronger runner. So specific strenthing wins out.
Specific stength training involving running, hill sprints for Max. strength, Fast hill climbing-strength endurance , Hill climbs-Fatigue resistance and movement drills that along with core work areas of weakness that can help with running economy at different speeds.
I understand that weights and plyometrics can be used as well and do work. Here is the drawback as weights are less specific as hills and plyometrics risk health and absorption of training. Do plyometrics work? Absolutely but they will also injury you very quickly. All training is risk vs. reward. With Running being the most important activity in distance running why risk it?