I have noticed the same thing and have started using one those huge balls in my morning workout.
It is dark here when I go to work and when I come home these days, so for the time being I am hitting the gym in the dark wee hours of the morningtime.
After some time spent on the treadmill and one of the precor machines I follow up with stretches using one of the big balls.
I also sort of sit on the ball and walk backwards on it so I am literally lying on my back on it to do crunches and to stretch out my back.
Sure feels good too to use one of these to stretch out your back after a long bike ride!
I highly recommend the big ball stretch out for those abs.