I was on the Grand in November and used the fitness center twice a day. I would classify the facility as adequate but not on par with a health club given the number of passengers trying to use it. There were 5 treadmills that all are subject to a sign up sheet every morning when they open at 7am. In addition, there were 2 stair step machines, 2 eliptical trainers and 4 recumbant bikes. There was a good selection of dumbells, no freeweights and about 6 weight machines for resistance training. The weight machines were not available until 8am. They didn't want people dropping weight stacks on the machines disturbing the guests in the cabins below. They actually pull the pins from the weight machines and return them at 8am.
We found the facilty to be very busy every morning when they opened and on sea days. If we were not there they opened in the morning, we had to wait to get a cardio workout machine. Late afternoons, around 4, they were not as busy, so we did both times.