That is more an article topic than a Q&A forum one.
But think of it this way. What are you trying to accomplish with training? You are either trying to make your muscles contract stronger (produce more force), faster (produce more power), larger (increase hypertrophy) or be able to contract hard/fast for longer (strength and power-endurance). There are other things of course, but these are the key ones.
To do that you need to...
1) Load the muscles or movement patterns you want to improve. The key element here is selecting the best exercises to accomplish that. Basically exercise selection determines which muscles will get stimulated (so which will improve) and what coordination patterns will be programmed.
2) Train the qualities you want to develop. Strength, power, hypertrophy, resistance/endurance... you need to select the training parameters that will maximize the development of these qualities. If you want to improve the capacity of the muscles to produce a maximal amount of force and you decide to do sets of 20 reps with 50% of your maximum, you will not develop what you are shooting for. In that regard if the exercise selection allow you to load the proper muscles, the selection of the intensity zone (percentage of your maximum at which you train) will determine what qualities you are improving.
3) Give the muscles enough stimulation to force adaptation, but not so much so that you will exceed your capacity to recover. Training is like getting a tan: with the proper amount of sun exposure your skin will get darker. Too much time under the sun (especially if the sun is intense) and you will burn, too little and your skin tone will not change. It's the same with training and this is where volume comes into play. You need enough mechanical work to stimulate changes, but not so much so that you "burn". The proper amount of volume is th3e trickiest thing to plan because what is optimal depends on individual tolerance for physical work as well as intensity of training; you can't tolerate the same amount of brutal hard intensity as you can low intensity work for example. So exercise selection determine the structures that will get stimulated, intensity determines which quality is worked and improved and volume is responsible for the magnitude of the changes taking place.
These are the "big 3" of training adaptations.
To these you can add...
4) Muscles might need to produce force under different circumstances/conditions. For example throwing a punch and holding an opponent to prevent him from moving require different types of muscle contractions. You need isometric strength (holding strength: being able to produce a lot of force without movement, or hold certain positions solidly even when under load), eccentric strength (yielding strength: being able to absorb external force and resist it without losing control), concentric strength (overcoming strength: being able to force a resistance to change direction and/or speed)... and even within these 3 major types of actions there are subdivisions... explosive strength, ballistic contractions, shock absorption, etc as well as actions combining various types of strength in one movement (reversal strength for example: absorbing an incoming force, stopping it's movement, reversing it and then projecting it in the other direction). All these types of actions and contraction types have different motor patterns. For example the muscle fiber recruitment pattern during maximal eccentric, isometric and concentric actions are different. This is why you cannot only train using one type of contractions and hope to maximize performance under all conditions.
5) You might also need to improve things like the capacity to recover your capacity to produce force during a very brief period of time. An athlete who can do a max effort then be able to recover 90-95% of his capacity to produce force in 30 seconds will have an advantage over and athlete who can only recover 60% of his capacity in the same period of time. Training density (the amount of work done per unit of time... or specifically playing with the rest intervals during training) can thus become an important variable to play with.
As for the training split, it's main role is simply to take the weekly workload you have to perform during a week to get the adaptations you want and divide that workload in a rational matter to avoid being unable to recover and show positive adaptations. In other word the training split should itself be determined by the training strategy you decide to use.
For example if you decide to use both a high intensity and high volume of work for a muscle/movement pattern you will not be able to train that muscle/pattern often. Not only that you need to organize your training in such a way that the brutal session doesn't have a negative carryover over another session. For example doing a brutally hard shoulder workout might negatively affect your capacity to train chest for 1-2 days (maybe even 3).
But if you decide to go with a lower volume approach you can train each movement pattern/muscle more often. So really the split is subordinate to the type of stimulation you decide to use. This is why I see it as a secondary training parameter.
This is a simplistic way of looking at training and performance. The subsection on the different types of contractions might have shed some light in that regard. Sports is not just about being explosive. It's about producing force under various circumstances.
I'll use myself as an example: at one point I did all my lifts from pins (for example bench pressing starting the bar 2" from the chest on pins on every repetition). During that time I didn't really pay attention to how I lowered the bar (I should have), sometimes I even almost dropped it down to save energy to get more reps in. I trained like that exclusively for about 4 months. At one point I could lift 425lbs on the bench press like that (starting 2" from pins, from a deadstart). When I decided to test my regular bench press I couldn't get 365 (I had done over 400 in the past). What happened is that I felt weak lowering the bar down, lost control, lost strength trying to bring it down properly and then lacked the capacity top stop the barbell and reverse it's action. My muscles were very strong CONCENTRICALLY (to lift the weight) but my eccentric and reversal strength were detrained.
While explosive/CAT is super important. If that's all you do you might lack performance in some type of muscle actions.
From experience THE MOST EXPLOSIVE ATHLETES ARE THE MOST PRONE TO INJURIES. I always compare explosive athletes to F1 racing cars: high performance but very fragile. IMHO it's because their explosive concentric strength is out of balance with their other types of contractions and their tendon strength (which is strengthened better with an emphasis on eccentric and slower movements) is too low for their capacity to produce power/strength.
For example I believe that in Crossfit the high injury rate is in part due to a lack of eccentric/isometric strength relative to their concentric strength. All their movements are done as fast as possible and often lowered fast too, without much of an effort to control or slow down the weight (to go faster)... kipping pull-ups (especially butterfly kipping), kipping handstands, Olympic lifts, box jumps, KB swings...all are lifted explosively and lowered without slowing down the resistance. As a result they become super efficient at one type of muscle action and stay weak in others.
Yes and no. Changing the type of muscle action will work. But it has to be done in a smart way to elicit certain specific changes. And there is a place for not trying to explode on the way up of a rep, even on big movements.
For one thing, always trying to accelerate as much as possible can lead to getting very strong in certain ranges of motion and weak in others. Why? Because when you become super explosive you can produce so much power/acceleration in the initial part of the range of motion that the bar gets a lot of momentum. So in reality in the later parts of the movement the bar provides a lot less resistance because momentum takes away from the resistance: if the barbell is moving up with acceleration you don't need to push it as hard to continue pushing it up... for example it's much easier to push a car that is in movement than a car that is at deadstop.
Chains and bands obviously help with this: the increase in resistance in the later part of the range of motion compensate for the decrease in resistance due to the momentum. And these are great tools. But they also make the movement more neurologically draining and this has to be taken under consideration when programming the training. Lifting using only the required force production (trying not to produce maximum momentum/acceleration) can allow you to strengthen the whole range of motion equally at a lower neurological cost.
And while being explosive is key in sports. Do not forget that strength is the foundation on which power is built (power = force x velocity... or force x distance/time). So while explosive/CAT movement should play a significant role in an athlete's training program, methods building overall strength need to be used to.
Another thing to consider is that a lot of athletes lack stability/postural strength to maintain proper lifting form when doing explosive exercises. You will see this mostly with lifts like squats, front squats and deadlifts. Some guys will have perfect form when they simply focus on lifting the weights, but when they try to be explosive their technique and posture goes to hell. And often it's not even due to not thinking about proper technique, it's that the muscles involved in maintaining perfect lifting posture aren't strong or efficient enough to withstand the sudden change in speed and force production.
It's loosely based on a 1976 (or is it 1974) Russian periodization plan than was used for squats by Olympic lifters. It was then adapted by Dr.Fred Hatfield (nicknamed Dr.Squat because he has a PhD and a 1014lbs squat) for a full powerlifting cycle. Both my 915 and Power Look program use that periodization approach as a foundation but it's modified a bit.