Sure, why not?

Helps when you have a small amount of work and might strike a conversation if there are mutual interests.

I consider it is a good idea to put your skills not only in the architecture field. Just mention it like "by the way" :)

Wish you good luck working on your CV!

That's impressive, well-done. For a high-level achievement on that scale, definately include it (as opposed to, say an 'interest in photography' or otherwise vague space-wasters). Breadth of background, especially those of a competitive nature, is always a great talking point, demonstrates commitment, and functions as an excellent identifier to potential employers ('the athlete applicant'). I've had a similar background, balancing architecture with pro sport, and its always been a beneficial tandem, even leading to potential lines on business development and obtaining work.

Yep - put it in there. Shows time management and dedication. Plus, you never know what will be the hook that gets you hired. Maybe the hiring manager also played the same sport. If so, you already stick out to them.

Definitely include, but keep them 1) succinct, and 2) down at the bottom.

I agree, put them in but at the bottom and out of the way of the main relevant info.  When I got hired, I had my clubs/activities from university at the bottom in a short list.  They asked me during the interview about my involvement, what the clubs had achieved, and why I was interested in being in those clubs specifically.  After I was hired, I found out that my boss looks at the hobbies, clubs, etc., to tell if someone will fit into the office culture and if someone has stuff in common with other staff.  When he hires someone new, he'll introduce the new person and give a little talking point from the interview to help break the ice. 'Here's Jason, and he likes building furniture and reading about cars.  Stop by and say hello when you have a minute!' Something like that.