American Parkour

You'd probably be better off just combine the extra exercises from B into A and doing it 3x a week

I think he's asking if you could do it while keeping your legs almost perpendicular to the ground the entire time. I've seen it done on rings but I don't recall seeing it on a bar.

BryanGThe point at which Parkour-like practical training methods stop developing strength is the point at which developing strength stops being practical. Practical training methods give you what you need, nothing more, nothing less. You don't need any more than what you need for practical purposes.

Your argument makes the same fundamental mistake that I've pointed out numerous times in this thread alone, namely that it considers only physical strength. Yes, specialized strength training develops physical strength faster, but we need other skills besides physical strength and specialized training makes developing those other skills harder. The harm specialized training does to the development of those other skills outweighs the benefit to physical development, because each of those other skills are just as important as physical strength, if not more so. The most efficient way to develop all the skills you need is to practice them all at the same time and develop them together.

This has also been covered earlier. Impact is not compulsory in Parkour. There are many obstacles and many ways of moving past them which do not require impact, and if you're new to Parkour then obviously you should start with what you can handle rather than what you can't. Wriggling, walking, crawling, balancing, climbing. Parkour can be scaled to suit anyone's starting condition.

Yes, you can train for every situation. You can't become perfect at dealing with every situation, but you can improve your ability to deal with every situation. You do so by developing your most fundamental abilities, that are the building blocks of all complex tasks. Positive attitudes, relaxation, concentration, strength, speed, balance, self-control, self-determination, to name just a few of the abilities that practical training methods like Parkour help you develop. Adaptation, perception of surroundings and learning to make mistakes safely, three that specialized strength training hinders your development of.

The only goals that specialized strength training is more effective at achieving are those goals that are purely physical in nature, such as doing a big jump that you've seen in a video. If you want to find your own things, discover and take your own path (which is the stated goal of Parkour) then you need far more than just physical development. It is up to the individual to decide whether they want to progress along their own path or to just copy others, but all I'm doing here is explaining the purpose of Parkour and why Parkour's method is the best method of working towards that purpose. If you don't share that purpose then of course, there is no reason to practice Parkour.

It causes an imbalance because it develops some skills more than is necessary (physical strength), develops some other skills not at all (the ability to judge the real environment), and actively makes it harder to develop some skills (the ability to adapt). Imbalances are bad because practical tasks, i.e. the only time you need these skills, require a balance of strengths in many skills.