The foundations of exercise science were laid in prehistory and haven't changed since. There are a finite number of joints in the body; and so there are a finite number of movements it can do. In reference to progression, matters are equally straight-forward. Taking a block of time, increasing the demand in a systematic manner within that time, and all in order to produce a desired performance or physiological output is what's known as periodization. It works on a principle of progressive overload within a prescribed timetable. No matter what late night infomercials or clever web advertisements tell you, it's not new.
Russian strength coaches created complicated, intellectually rigorous and highly effective sports periodization for Olympic athletes more than 50 years ago. In fact, the ideas of homeostasis and adaptation in the context of athletic domain come directly in fully refined format to us from the late 19th century. Thank you, Walter Bradford Cannon, and (later) Hans Selye.
So what's the commotion all about when a new craze hits the scene? I can't tell actually. Every ancient society with a military had codified, effective exercise periodization AND an equally demanding and stratospherically potent mind-training. They needed the fastest, most powerful, most agile, most enduring force of human beings possible. Why wouldn't they?
I'm not trying to take anything away from anybody so much as put our modern practices in their proper historical context. Does anyone really believe that ANY gym is producing athletes who could go toe to toe with the AVERAGE Spartan hoplite?
From the perspective of strength training, progressive overload has been around about as long as we can tell in written history. The sixth century BC figure, Milo of Croton, was allegedly capable of picking up a grown bull on his shoulders because, since childhood, he had daily lifted a baby calf, it ever growing bigger while he was ever growing stronger.
Even after removing storytelling embellishment, it doesn't appear that our highest performing athletes have broken any ground that someone else didn't break thousands of years ago.
From the perspective of endurance training, all modern feats are a joke. Ultra-marathon, you say? Cute. The Native American Raramuri would run 200 miles through deadly canyon terrain, barefoot, without a break, and without someone handing them a goo packet or Gatorade every few miles.
Ironman or Tough Mudder? Read Xenophon's Anabasis. Over ten thousand Greek infantrymen traveled over 2000 miles on foot, over frozen mountain ranges, AFTER running out of food, with the added weight of supplies and arms, while being constantly hounded by a bloodthirsty army ten times larger.
MMA? Just a rehash of the ancient Pankration. Ever hear of the Colosseum, gladiators or Greco-roman wrestling? Almost three millennia ago there were commentaries detailing the intricacies of one school's technique on a heel hook or arm bar versus another. Frankly, just think about the name "martial arts." Their eastern forms long ago created what people are just now doing in Pilates, Barre and Yoga. If the Indus Script is ever agreeably deciphered, we may find that certain poses or breathing techniques in vogue now at your local studio date to 2600 BC. Rest assured that even before that Egyptian Pharaohs were learning what stance dealt the most powerful blow to an assassin without risking injury to oneself.
So what's the breakthrough? I don't know. In every other time and place, incredible physical feats were accomplished by the everyman. So our parle of fitness to the everyman isn't a breakthrough either. We do seem to have gotten a better hold on injury prevention, perhaps. Although, one wouldn't know this from reading any of the thousands of posts on Insanity Workout Injury forums.
And thus, the matter stands settled. Any movement that the human body can do has been done. I mean, really, each muscle group has only ever done what it has always done. Nearly every manner of progress has already been devised. Slap whatever label on it you like. As you try to create the impression that you just today innovated what the ancients long since invented, those who read this know the truth.
There does seem to be something somewhat new. I hesitate to say it, but it appears completely novel: you can grow stronger as you grow older. For the most part, all of the incredible feats of old were largely done by the young. In the modern era there are young feats being done by the old. In fact, our concepts of what constitute "age" are having to be rethought. A recent study showed that even 90 year olds will IMPROVE, not just maintain, when executing strength training.
You see, simply put, there are two types of muscle fibers. Type I is for endurance. It is trained by and responsible for long bouts of low level exertion. This is why "older" people can generally manage to stand or walk for relatively long periods of time if they haven't become completely sedentary. Type II is responsible for everything else: strength, power, speed and balance. It is trained most safely by strength. This is why "older" people might spontaneously lose their footing even if they're relatively active but don't do strength training.
And we now know that Type II muscle fibers aren't predetermined to deteriorate as the years go by, but only if they're left unchallenged. So challenge them. That means "heavy" resistance.
Strength: that is the measure of value for any new fitness fad. Not newness. There's nothing new under the sun anyway. Forget about who is endorsing it or whether or not it's an inventive technique from researchers at the such-and-such Institute. Does it challenge Type II muscle fibers, safely, effectively, with some sensible form of periodization? If so, then it could give you a shot at reversing aging. And if old can become young, that would actually be new.