I really love running!

Currently Recently I returned to practice a sport that I <--always capitalize the single letter "I" really like a lot: running.
I don't do it necessarily for questions of physical appearance or for to lose weight.
Actually, I do it for I can to pass a the time without think in nothing while not having to think.
When I'm running I focus simply in on my breath for do it the best way possible and with that
can to improve my time in every back and also get to run more and more. <--- I'm not sure how to correct this as its a bit confusing. You could simply say this: When I'm running I focus on my breathing techniques.

I know that I still can to improve a lot and I will continue practicing!

I really love running !

Currently I returned to practice a sport that i really enjoy : running.
I don't necessarily do it for physical appearance or to lose weight.
Actually i do it to pass time.
When i'm running,I simply focus on my breath so I can do it the best way possible; in doing that I can to improve my time and increase how far and long I can run. 
I know that I still have a lot of room for improvement, so I will continue practicing !

I really love running !

Currently Now days I returned (Not past form as you still doing it) to practice of a sport that i really like a lot : i.e (That is) running.
I don't am not doing  it necessarily for questions for sake of physical appearance or for to lose weight.
Actually i am doing it for I can to pass a  time without thinking in nothing.
When i'm running,I just focus simply in on my breath for to do it in the best way possible way and with that i can to improve my time in every back attempt and also get to run more and more.(I correct it thinking that you want to improve your time for distance cover) 
I know that I still can to improve a lot,and I will continue practicing !