Hardest Pool Event?

the 200 breaststroke for me...

I'm a breaststroker and that one is definitely brutal too!

The 200 backstroke is pretty tough!

a few years ago one of the Swim magazines did a poll of the hardest event. The winner was the 200 breast. But of the 200 fly they said “it’s like a Game of Thrones, episode everybody dies.”

400 IM is a lactic acid bath for sure. Near the end of the breaststroke I find myself looking forward to switching to freestyle, only to find when I do that my limbs no longer operate.

Still, the 200 backstroke can be worse. Sometime I can't walk afterward.

I can't swim breaststroke well enough to judge the BR events.

400 IM is rough.  Each transition is pain in addition to the individual 100s.  Non meet events: An hour postal is rough if you go straight and push it.

The 200 fly is the hardest for me, but I like the challenge and feeling of accomplishment each time I complete it, even if I am slow.  I'm a breaststroker, but I have a hate-hate relationship with the 200 breaststroke.  All love is lost after the first 100! 

Upon reflection this depends heavily on how one defines "hard". If hard=painful, then I will stick with my 200 BK & 400 IM comments. I think the same two events come out on top for required skill too. The 400 IM has all the strokes and all those tricky turns. Backstroke is the most technical stroke. BUT...
if "hard" means "difficult to get right" then I think it is a near tie between the 200 FR and the 50 FR. I think I have swum the 200 fr correctly in competition about once in my entire life, and I'm still waiting to get the 50 FR right. Somehow the 100 doesn't seem so tricky.

Any race 200 and longer is hard if you swim it right. I think 200 breaststroke is especially hard because it’s technically difficult and you’re using the large muscles in your legs so much you’re really generating a lot of lactic acid. An advantage is in a 200 breast if you go out too hard you can alter your stroke and still finish albeit in a lot of pain. 200 fly if you go out too fast you risk disqualification. It hasn’t happened to me, at least not yet, but imagine swimming a 200 fly and then finding out it doesn’t count.

Actually, that happened to me at the 2014 Long Course National Championships in Maryland (as if 200 scy fly isn't hard enough!).  One of the (new) officials threw up her flag and DQ'd me at the last turn and claimed I had an uneven kick.  A few minutes later I was called out on the intercom into the officials office and told it was overturned.  (I actually had a video of my race that Bruce shot and offered to show it to the official to validate the correct decision to overturn the DQ.)  It was a long story I won't get into, but suffice it to say I was a happy camper when I walked out of that office with a medal around my neck!  It was a nice souvenir after a lot of frustration-- especially since that is one thing I NEVER get wrong in fly, because I can feel my feet touching on every kick.  Accuse me of having a really slow fly, but I've never gotten a legitimate DQ!