A little late here but have something worth sharing. I grew up with a buddy who has CF, we were on the same soccer team for years in the most competitive league in Texas (he was one of our best players). He also played football in middle school as a running back I'm pretty sure (in Texas at a big school, so not exactly an easy feat having CF or not). We also went to the same college, where he decided to try out for the schools rugby team. Never went to a game but I'm pretty sure he ended up starting for them, they were a nationally competitive team every year. Dude got pretty jacked during this time. After graduating he got really into rock climbing and appears to be really good at it from what I can tell.

-I did not post this to 'prove you wrong' I know you were just speaking from your experiences, just wanted to share mine. Don't know for sure but I assume the severity of symptoms can vary depending on the person. People who did not know him well usually just thought of him as that "kid with CF" but no one thought of him as "sickly", he was popular in HS and played for the HS soccer team at a 6A school. Great athlete and a really cool guy, I know he struggled a bit with probably facing a shorter life expectancy but always kept a positive outlook and makes the best of every day.