1. SWORD FIGHTING GYMS ARE REAL GYMS!

In actuality, this regal realm I wandered into is the first floor of Forteza Fitness, a multilevel gym in Chicago dedicated to both modern methods of fitness training and the old ways of the sword. They practice the latter form of alternative fitness during boot camps and fitness classes, whipping students into Marine-like—or perhaps knightly—shape. Their expertise lies in teaching real, ancient techniques of fighting opponents with bladed weapons. This specialty even shapes their medieval boot camps, which is what I chose to attend instead of a more traditional sword fighting class.

When I walked in, three men were already at work scaling a cargo net suspended near the back of the gym. A trainer, Jesse Kulla, greeted me pleasantly at the front desk. I scribbled through my paperwork quickly, eager to start stretching and warming up for what Jesse described as "a real slobber-knocker."

2. MEDIEVAL WORKOUTS CAN INCLUDE BURPEES.

To start the class, Jesse and fitness director Keith Jennings had us pair up. They then overviewed the day's strength and conditioning workout, pausing to demo any unfamiliar exercises. Keith performed one particularly devilish move called the burpee pull-up: he laid chest-down on the floor, leapt upward to complete a pull-up on a bar above him, then returned to his prostrate starting position. Alternative fitness or not, you'll still recognize some familiar moves in this fitness training regimen: the class began with 30 regular burpees before we moved on to those burpee pull-ups.

My partner and I proceeded in no particular order, simply trying to give our arms a rest between stabilization pushups, pull-ups, and cargo-net climbs. It seemed to be an intimidating number of exercises that were listed on the chalkboard, but we finished in about 45 minutes, as did most of our classmates. Then, we moved on to the martial-arts portion of the day.

3. Boxing and broadswords go hand-in-hand.

Though I'd heard that the trainers are known to break out the practice broadswords and swing them around a bit, today they chose to focus on boxing. They led each pair to various standing and hanging punching bags throughout the gym, and the duos raced each other to complete combos that Keith called out.

4. Knighthood leaves you sore, like, really sore.

I found the combination of circuit training and light combat training to be both fun and incredibly challenging, and the soreness ended up sticking with me for a couple of days. After class, once I managed to get up off the floor, I chatted with the trainers for awhile, and learned that Sunday mornings are their most intense workouts. The other boot-camp classes throughout the week typically include fewer plyometrics or pull-ups. "Which doesn't mean we don't work hard," Jesse assured me. I believed him.

Check out the fitness tips I gleaned from my first class, sure to help any beginner during his or her first medieval workout.

• Try it if you want to build strength or just like swords
• Don't go if fast-paced circuit training isn't your thing
• Beware of overdoing it—the trainers expect the students to proceed at their own best pace
• Come prepared with just water and a towel, if necessary
• Wear good shoes and comfortable workout clothes that let you move
• Intensity level: You'll feel sore for a day or three

This article was originally written by Groupon staff writer Zach Bosteel in 2015 and has since been slightly modifiedby our editors.

Photos by Timothy Burkhart, Groupon.