When I was much younger man (Im 47), I trained pretty hard. I wanted to see once how many sit-ups I could do at one time. I was in really good shape at the time, and easily broke off 50-75 rep sets. I got down and pumped out 800, EIGHT Freakin' HUNDRED. I missed 3 days of work, and had to roll out of bed to use the bathroom the first two. But DAMN!!
I remember doing 75 sit-ups with no problem on an incline bench when I was younger. Wonder how I'd do with that now.