geez, i'm usually good for about 1.5 - 2 hours, at best - not any particular part of the body, just an overall sag in stamina. i start blowing pop-ups and take-offs, which makes me eat it more, which wears me out faster etc etc - snowball effect. and i don't even mind - as mentioned earlier in the thread, literally one good wave salvages a whole session.I'm on this one. I don't wanna trash my shoulders, so I surf max 3 hours and don't do any long paddles.