Importance of Posterior Muscle

I do follow a number of karate websites and channels and one of my favorite has to be KaratebyJesse. It is choke full of wonderful information about karate, and some of his articles are down right witty. If you love to practice karate and love to laugh, his website is the place to be.

In one of his article, he wrote about the importance of posterior muscle, or the posterior "chain." Here's the excerpt:

Humans have a big brain, right? We’re smart. But when it comes to fighting, we are physically weaker than many animals! Dogs, cats, ants, horses, rats… they are stronger, more agile, much faster and more athletic than a human will ever be. So let’s use our smart brain to study animals: Does a horse have abs? Nope. Does a dog have huge biceps or pecs? Nope. So why do humans insist on training these “useless” show-off muscles all the time? Animals have incredibly strong posterior chains (muscles on your back, hamstrings, glutes, triceps, lats etc.). Focus on those instead. That’s where beastlike power comes from.

Below is a rare photo (as I've stated previously, any information on Nakamura Sensei is rare and I'd say quite valuable) of Nakamura Sensei practicing karate. Notice his back musculature:



How did he get such a phenomenal posterior muscle chain? Did he lift weights? Calisthenics? Or practicing kihons repeatedly? I'd guess a mixture, or a partly genetic.

Interestingly, the "gi" pants he is wearing looks more like a Korean hanbok pants. He was from Pyong Yang after all so it's likely that he did not abandon his ties to Korean culture. More about this later.