Rolling down a hill at 30 mph

[az]

try to stick to frontcrawl, butterfly and backstroke though; if my swimming teacher at school was to be believed apparently you can do some serious long term damage to your knees kicking for breaststroke

it is a great workout though, and something you can keep up into old age

 

[Lord Shade]

I do a lot of running out doors (and when its cold on an indoor track, though I could do it outside as well), mostly I run about 3-6 miles on average. I also do a bit of lifting. Should do some more honestly.

 

[cantab]

try to stick to frontcrawl, butterfly and backstroke though; if my swimming teacher at school was to be believed apparently you can do some serious long term damage to your knees kicking for breaststroke

I've never heard that before. Until I see some proper research on it, I'm calling bull. OK, maybe if you try to do breaststroke at racing speed you could have problems, but ANY truly competitive sport is liable to cause you injury and damage (since to be competitive, you need to push the limits of your body).