With increasing regularity, more and more mixed martial artists are looking at alternative ways to up their cardio. Often times running for 45 minutes at a time can not only be hard on the knees, hips and back, but it also might not adequately prepare a fighter for the intermittent nature of combat sports — the sudden bursts of explosive energy needed to capitalize on your opponent, when you "smell blood" so to speak.

For many fighters, the VersaClimber is serving that role. Marketed as "one of the only true total body, non-impact, vertical trainers available," the VersaClimber does just that. Its non-impact nature allows an athlete to train without jarring his or her joints like running so often does. That’s especially important for heavier athletes.

The VersaClimber also engages all the major muscle groups that are used in grappling, boxing and jiu-jitsu — something a treadmill cannot do.

But perhaps what’s most importantly from a fighter’s perspective is that there are no top-end speed limitations. Fighting requires high bursts of energy intermittently over a prolonged time period. When you’re training on a treadmill, for example, and you want to increase your speed, you have to push a little button and wait for the motor to catch up with your request. That downtime doesn’t translate very well into the ring or cage.

The motor pushing the VersaClimber is your own. If you want to sprint, go for it. There is no downtime. The design allows for unlimited sprinting capabilities.

I recently asked UFC veteran Stephan Bonnar about his experiences with the VersaClimber. If you recall, "The American Psycho" was originally slated to face Matt Hamill at Fight Night 13 back in April 2008; however, a severe knee injury forced him off the card. After undergoing reconstructive surgery, Bonnar needed to find a way to push his cardio, without the toll to the knees that often comes with running.

That’s when Bonnar’s strength and conditioning coach, Kevin Kearns, encouraged Bonnar to try the VersaClimber. You can watch Bonnar explain one of his favorite workouts on the VersaClimber here. I asked Bonnar about how difficult it was, post-surgery, to return to his old workout ways.

This is what he told me:

"Usually I like running up hills for my cardio. And that was just out of the question now. Probably about four months after my surgery, I got the VersaClimber and started using it. It really makes you work, so there’s no cheating on it. You’re fighting all that gravity, and it’s so easy on your joints, there’s no impact on the knees or anything like that."

The VersaClimber has aided Bonnar in his nearly yearlong comeback. We’ll see just how well his cardio has improved tonight at UFC 94: "St. Pierre vs. Penn II." But in the meantime, Bonnar has nothing but good things to say about the device:

"Even though my knee was still not fully healed, just getting on the VersaClimber and going to work didn’t bother it at all. And it’s great for my cardio, because, like I said, I hadn’t been able to do much the previous couple months. So I started from the bottom, and it helped get me back in shape pretty quickly. Even now, I’ve had my knee scoped before, I’ve had this surgery and they took out more cartilage. So as far as running up the hills like I used to, I kinda scratched that from the program and replaced it with the VersaClimber."

As a strength and conditioning coach, Kevin Kearns’ knowledge of low-impact, high-results conditioning makes him a hot commodity for some of the hardest working fighters in mixed martial arts. In addition to Bonnar, Kearns’ clients include Kenny Florian, Marcus Davis, Kurt Pellegrino and Nate Quarry — the latter of which also had to come back from a devastating injury with help from the VersaClimber. Kearns turned Quarry onto the device when he was recovering from back surgery that kept him from competing for nearly two years. To hear Kearns explain it:

"Nate Quarry is 36 years old, and he said, "Look, Coach, I can’t do this anymore, my knees are just getting beaten to death by running on the road." So we recommended the VersaClimber a) because it’s a killer cardio workout, and b) it’s non-impact. There’s no impact on the joints, there’s no impact on the spine. You’re actually elevated, and you’re not on the ground. And I think that’s just hugely beneficial for these MMA fighters, not to mention the cardio conditioning elements and the interloping conditioning elements, specifically for MMA."

How it aids mixed martial artists specifically is due to the explosive nature of the sport. Sure you have to be in shape enough to fight for 15 or 25 minutes at a time — but you also need to be able to unleash on your opponent when you see an opening, and not gas yourself out in the process. Kearns says the VersaClimber is the perfect conditioning tool to meet those needs.

"It’s very easy to turn it up and do any type of interval workout. You’ve got non-impact, you’ve got upper and lower body working at the same time. When you run, you are activating your upper body, but there’s no resistance … unless you want to (use) hand weights. So when you look at the specifics of the cross-crawl pattern of the VersaClimber, because it’s in an X fashion, it’s very specific to what MMA needs. It’s opposite arm, opposite leg. And that’s basically how you’re punching and kicking anyway. So it’s very easy to design circuits that are hugely explosive in short bursts, which is pretty much what you’re going to run into in the ring. For all intents and purposes, you can get a lot of benefit in a minimal amount of time."

Florian, who played Division 1 soccer at Boston College, has worked with Kearns — who he calls Dr. Evil — for years and is known for having tremendous conditioning. Kearns says that the first time Florian tried the VersaClimber, he was just 15 minutes into his workout and was shocked with how hard it made him work. He even came up with a nickname for it, although it’s not safe to print here.

Kearns trains about 15 professional fighters, most of whom are featured in the UFC and WEC. When taking on a new client, the first thing he recommends his athletes is the VersaClimber. He should know, he’s had one in his own home for 12 years.

To learn more about the VersaClimber and how it is suited specifically for combat training, check out their website here. To learn more about Kevin Kearns’ MMA conditioning series available on DVD, go here.