Originally posted by: BeauJangles
I think you'll find your endurance a bit better if you pick a set number of reps (say 15) and do those, break for five or ten seconds, and then bang out fifteen more. That gives your body micro-recoveries, which can work wonders when you're trying to do 400 reps.
On Friday I just repeated FGB for the first time. I had a 68 pt PR. Part of that is obviously due to superior conditioning, but I think that taking the time to rest at set intervals really helped me. The score for each round reflected that -- my best round was the third.
As for sit-ups, they are incredibly taxing if you're doing them right (which it sounds like you are). I always find my abs burning at about 50 - 55 reps, but usually try and push through it. With more regular rest (15 reps, 5 - 10 second rest), I find it much easier.
Hm, that makes a lot of sense actually. I think I'll give this a shot next time a similar workout comes along.