I once read this quote from Forbes: "for each generation to make progress, it must view the one before it as barbaric."
These days, exercise is all about muscle and strength. But in the future, we will look back on these concepts as barbaric. Why? Well, for a lot of reasons.
We're starting to realize that building muscle is not as valuable as enhancing function, i.e. those with great coordination and balance tend to be much more athletic than those with great strength.
I thought yoga was fad. Back in the 90s, all the ladies and metrosexual men were dashing into yoga classes and workshops. (I think Madonna had a lot to do with it) I was sure that yoga would be dead in 10 years. I was wrong. But the way I see it, many who practice yoga still talk about how it builds strength.
The hottest emerging exercise is called functional exercise or (gulp) "functional fitness." The concept is that conventional weight training isolates and builds muscles, but it doesn't "teach" those muscle groups to work with other muscles. So "functional" movements focus less on raw strength and more on integration and coordination. These are more like whole-body exercises that will help you lift a toddler out of a car seat or carry a 60-pound suitcase down the stairs.
Doctors and trainers are closing in on the exercise of the future. They know functional is better than strong, and that stretching (yoga) is really important. Tai Chi is all that and a bag of chips.
Tai Chi is all about coordination. In fact, the movements are slow so that you can fine tune your coordination. When you move slowly, you begin to feel which parts are not linked up. In the west, we view "coordination" as aggregate. But in Tai Chi, there are six coordinations: three exterior (shoulders and hips; elbows and knees; hands & legs) and three interior (heart and intention; intention and chi; chi and strength). At higher levels, all six must also coordinate.
Tai Chi is also a phenomenon of stretching. Sure, yoga gets you stretched, but not like Tai Chi.