Exactly what else do you think they should do - fall asleep for 20 years, wake up, and return to work? Do me a favour!
Prisoners need access to a full weights room to give them a chance to remain healthy and something to do to give them an interest. Likewide, many take up new interests like taking a degree etc. As for having the power to rip someone's arms off....wtf.....If they wanted to do that, they'd use a gun anyhow. If taxpayers are spending a fortune funding state prisons, the least they deserve back is that some effort is made to rehab these guys back into society. Depriving them of something basic like a gym will never happen. As for the laughable "make prison as hard as possible" agrument that some people out there use, I think being away from your home, family, and everything you've ever known isn't a bundle of laughs anyhow.