"Prison workout" — what is the origin of this term?

Solution 1:

A prison workout refers to a set of exercises that can be done in a small indoor space without much equipment—as in a prison cell.

Solution 2:

Different authors appear to understand "prison workout" in at least a couple of different ways, although both are tied to the underlying notion of "a fitness routine performed by someone in prison." Here are a few examples.

From James Parker, Turned On: A Biography of Henry Rollins (2000):

Given a limited time slot and an audience of partially-interested funk-jocks, Rollins Band hit the situation like it was a prison workout, like men turned loose on a set of free weights and a worn bench and forced to conjure maximum efficacy from half an hour.

The emphasis here is on old and minimal equipment and (especially) a very short workout period.

From Larry Palmatier, Crisis Counseling For A Quality School: A Family Perspective (2013):

When members of prison gangs gain their release, they generally return to their old communities, where they become folk heroes for the local kids. They have buffed up their muscles in the prison workout facility, and they show no fear.

Here, again, one imagines the "prison workout" as involving exercise in a room and on equipment designed specifically for that purpose. The practical shortcomings of the equipment and the limited time available for using it are not points of concern in this example.

From Jonathan Ilan, Understanding Street Culture: Poverty, Crime, Youth and Cool (2015):

Indeed, a recent phenomenon is the celebration of the 'prison workout' amongst fitness enthusiasts who view it as a simple and cheap means of improving form [URL omitted]. This involves exercises that are performed without weight-lifting equipment (which is easily weaponizable and thus generally not allowed within individual prison cells).

And from John Fuller, A Day in Prison: An Insider's Guide to Life Behind Bars (2017):

One ex-con, Coss Marte, was featured in Men's Health Magazine when his fifteen-minute body-weight prison workout went big on the outside, a five-move routine he developed at the Greene Correctional Facility while stuck in his cell. He certainly made the best out of hard time.

In these two instances, the focus of "prison workout" is on exercise designed to occur within a prisoner's cell, rather than in the prison weight room. Indeed, other books refer to it as "cell workout."

Although Coss Marte receives special notice in Fuller's book for having devised and/or promoted a particular prison workout routine, Marte went to prison in 2009—long after "prison workout" had begun appearing in print. For example, from Ian Coutts & ‎Dwight Allott, Do Nymphomaniacs Really Exist?: The Ultimate Q&A for Guys (2007) [combined snippets]:

There is a prison workout that involves no equipment but will give you the strength to survive. Let's turn to Ken Andes, a New York State acupuncturist and martial arts enthusiast. Andes has never been in prison, but in the late 1990s, while working toward a degree in social work at Rutgers University in New Jersey, he interned at a drug rehabilitation clinic for inmates at nearby Rahway Prison.

"I ended up reading a ton of material on rehabilitating prisoners," Andes recalls. "One thing I came across was this manual written [anonymously] by a really old prisoner who had been in the system for years and years. He wrote it for new prisoners on how to survive in the prison system. I was reading it because it had many psychological tips for adjusting to prison life. But there were also exercise routines in there."

Apparently, says Andes, these routines were perfected in a prison where the cons were only let out briefly every other day and did all their exercise in one room. The book features that classic favorite of sadistic high school gym teachers: the burpee. From a standing position, drop into a squat, then kick out your legs behind you. Then do a push-up, pull in your legs and spring upward, jumping clear off the ground and throwing your hands over your head.

"For a workout," Andes explains, "an inmate would stand on one side of the room and do twenty burpees without stopping. Then he would walk to the other side of the room and do nineteen burpees without stopping. Then walk to the other side. ..."

Andes doesn't specify the age of this manual, but he encountered it in the late 1990s—and it clearly describes a no-equipment prison workout.