I Have an odd habbit i got myself into, it started because i was realy tired after doning a set of weighted crunches and needed a break, so i started streching something for 30 seconds inbetween each set of situps cruches ect.that day and found it realy gave me a good full body strech by the time I was done with mysit-ups that day so i contiued to do it.

J/w what others think of that, is it good to strech inbetween sit-up sets?