As I wrote in the last entry, Baduanjin the Eight Trigrams Boxing is easy, briefquick and efficient.

"Brief" works here but "quick" sounds more native.

It might have been kept this way sincefor 1200 years ago.

The second reason is that after practicing Baduanjin, some people found it useful after practicing Baduanjin.

It might have been kept this way since 1200 years ago.

Technically you can say "It might have been kept this way", but it looks more natural to have "It might have been this way"

Then Taoists then developed it in the Song Dynasty, approximately 800 years ago.

I think there are three reasons why Baduanjin become more and more popular.

You can start your sentence with "Personally,", though the way it is now is also fine

The first one is that after COVID-19, many people haved some lingering physicalresidual health problems.

Those problems may be not be easy to recover from, or too tiny to userivial to need medicines.

SoThus, people try to get some help fromimprove their health through exercise.

So they told their friends about it and encouraged them to try it too.

You should connect this sentence to the previous one, or begin your sentence differently.

And the third one,- which I think it's an essential one for myself,- is that the only change you need to make in your daily life is to get up 15 minutes earlyier.

Time versus gain.; it's a bargain!

It's a bargain!

You should connect this to your previous sentence.

It might have been kept this way since 1200 years ago.

That's why it's a little similar to Taichi, the most famous form of Taoist Koungf Fu.

I'm not sure whether Kongfu is correct or not, but it's usually spelt Kung Fu or Kungfu in English.

I think there are three reasons why Baduanjin is becomeing more and more popular.

Those problems may be not be easy to recover from or too tiny to ustake medicines for.

The second reason is that some people found itBaduanjin useful after practicing Baduanjinit.

And the third one, — I think it's an essential one for myself, — is that the only change you need to make in your daily life is to get up 15 minutes early.

When you want to interrupt the sentence with a thought or remark, it is better to use dashes. You could also use parenthesis here.

It might have beenwas probably kept this way since 1200 years ago.

I think there are three reasons why Baduanjin is becomeing more and more popular.

Those problems may be not be easy to recover from or too tinyrivial to use medicines.

The second reason is that some people found it useful after practicing Baduanjin useful.