Recently, I realized that I had tried pretty much every cardio machine in existence except for one: the assault air bike. This wind-generating, low impact/high output exercise bike lets you control the resistance, depending on your effort. Picture an elliptical machine where you use your arms as well as your legs. Now imagine you’re sitting down while doing that. That’s an assault bike. They are typically found in CrossFit, used as a cardio component of the workout, but they are starting to pop up more in traditional gyms, too.

Over the last month, I started attending a gym called BeastBike, and the assault bike is a focal point of their programming. They use a combination of dumbbells, medicine balls, and the bike for a 20-minute, high-intensity workout that leaves you breathless by the end. (I know 20 minutes doesn’t sound like a lot, but trust me, it’s enough.)

Why I thought doing anything with the word “assault” in its title would be anything like I’m used to, is beyond me. As a trainer myself, I work out at least four times a week, so I’m no stranger to fitness, but at the end of my first class my lungs were on fire! The dumbbell portion of the class was typical for what I usually do to work out, and I felt very confident on the floor. Once I was on the bike, though, it was like I had never done cardio a day in my life.

AssaultFitness Assault AirBike — $828.00

Originally, $1000, currently on sale for $828

Chad Morse, owner of BeastBike, California, explains that the difference is in the resistance. “The harder you go, the more challenging it gets,” he says. “The bike will respond to that. You can be a beginner and it’s going to challenge you, and we’ve had former athletes here and it kicks their butt just as much. It’s such an ideal tool because no matter where you’re at in your fitness and conditioning level, it’s going to push you.”

The best way I can describe the difficulty of the assault bike as I experienced it, is that it’s like riding a bike up a steep incline while also pumping your arms. (I know that’s impossible but go with me here.) I honestly thought that because I was familiar with indoor cycling classes, I was going to be the beast the title of the workout was referring to, but the “beast” was indeed the bike; not me. I was humbled.

It’s like riding a bike up a steep incline while also pumping your arms.

Morse only compares an assault bike to a spin bike in the fact that there is peddling. Otherwise, that’s where the similarities end. “You’re also pushing, pedaling, and pulling so it’s really a full body workout,” he says.

I’ve heard it said (and probably even said as a trainer myself) that “the workouts don’t get easier, you just get stronger.” I can attest to this statement after spending a month doing my assault air bike workouts. There were varying amounts of time we spent on the bike—the longest being around two minutes at a time, and the shortest being three 10-second sprints with 10 seconds of rest in between each round. There was not one time I found it to be easy, but I do feel stronger.

Morse says he named it BeastBike because it’s a challenging workout, but also because you feel like you conquered something when you are finished. It is true. I am always tired, but I feel accomplished.

After using the assault bike on a regular basis, I’ve noticed I have better endurance when I do other activities, like outdoor runs. Because I like being able to do the most effective workout in the least amount of time (I’m a busy woman, y’all), the assault bike is a great cardio option for me.

“You can get in a really good workout in a short amount of time,” says Morse. “You’re able to do that because it works nearly every muscle in your body. You can’t say that about rowing, spin, or running. With the pedaling, pushing, and pulling, you’re using virtually every muscle and you feel like it’s draining when you’re doing it right.”

Overall, when it comes to the assault bike, my review is: 10/10 would recommend. Though it’s extremely challenging (probably the most challenging cardio machine I’ve ever encountered), it is scalable to your fitness level. I also appreciate that it’s a low-impact option for those looking. The thing I love the most though, is how accomplished I feel after using it. I am capital “P” pooped after every workout, but I also feel like I can take on the world… maybe not with my physical body, but with my endorphins.