Assault AirRunner Treadmill: In-depth Review

First Off - What is the Assault AirRunner Treadmill?

In short, it’s a high quality curved treadmill that is becoming increasingly popular in commercial gyms and crossfit boxes across America. It’s called a ‘manual’ treadmill because there is no engine involved.

By taking strides on the Assault AirRunner, your momentum starts to rotate the belt naturally. This happens a lot faster than you might think, and it only takes about 6 seconds to reach your desired speed.

It’s manufactured by AssaultFitness, who specialize in producing high quality endurance fitness machines that can help you burn a ridiculous amount of calories.

The AirRunner can be used for short distance training, long distance training, hill training and interval training, but it’s the shorter distance, high-intensity training where it truly shines.

What makes the AirRunner so good for speed training?

1) You Can Run At Full Pace – According to Assault Fitness, there is no maximum speed. My testing proved this to be the case. I managed to push the AirRunner to 16mp/h, and it was smooth sailing with every single stride. I’ve never run this fast on a standard treadmill and I don’t think I ever will.

2) Much Safer Than Normal Treadmills At High Speeds – On a standard treadmill, you know you’re taking a risk when you start pushing above 12mp/h. The slightest misstep can cause the belt to catapult your body into oblivion. It once happened to me when I was running on an electric treadmill and the speed dial got stuck moving upward. I was eleven years old and panicked. Eventually I made like a cannon ball and bounced off the belt. It wasn’t a very nice experience.

I know there are safety clips on most reputable electric treadmills, but the simple reality is that you can get launched if you’re running at a high speed and you stop paying attention or clip the side of the treadmill.

This is completely different with the Assault AirRunner, which has a much safer treadmill belt. Of course it is possible that you could fall while using a curved treadmill, but doing so won’t send you into an orbit that NASA would be proud of.

3) Way Less Noisy Than Normal Treadmills – Half the reason I don’t run at 12+ mp/h on a standard electric treadmill is because it makes so much noise. In a crowded gym, you draw a lot of attention to yourself when you start busting out full blown speed sessions on a standard treadmill. It becomes ridiculously noisy and it makes you look like an ostentatious twat, even if you’re just a nice dude just trying to get a cheeky speed session in.

This story changes when you run on the Assault Air Runner. I’ve been as high as 16 mp/h without anyone even blinking. It’s just so much quieter. You can literally sprint as fast as you can, without causing any commotion.

4) Super Light Impact – There’s something about the curve of the AirRunner that seems to reduce the impact force exerted on your feet, ankles and calves. I can’t back this up with studies, but I know exactly how my body feels when I go full tilt on the Air Runner. It’s just such a smooth and natural transition that electric treadmills will never be able to emulate. This amazing combination of high power, low impact running is very much a WIN-WIN for your body.

What Makes the Assault AirRunner better than a normal treadmill?

A) Easier on the body – Assault Fitness called this treadmill the ‘AirRunner’ because it literally feels like you’re running on air. Because the transition between each stride is so seamless and gentle, it’s pretty easy to understand why they gave it this name.

Over the long term I genuinely believe that using a quality curved treadmill (instead of doing all your running on the road or a standard treadmill) can significantly reduce the abrasive impact on all of the muscles and joints involved in running. This can only decrease the likelihood of getting injured.

For instance, when my calves are feeling tight (my biggest injury concern), I will avoid the electric treadmill at all costs until I have recovered. With the AirRunner, I often turn to it as a mild rehabilitation device.

The reason this is important is because the stats on running injuries are almost mind boggling. On runnersconnect, coach Jeff points out that “79% of runners get injured at least once during the year.”

Why do runners get injured so often? Because running on the road and on a normal treadmill can be extremely taxing on the human body. Fortunately, the AirRunner is much gentler on the body in terms of impact force, so you can literally reduce the likelihood of getting injured by covering more miles on a curved treadmill.

2) Enhanced Calorie Expenditure – I dive deeper into this topic a little further in the article, but to quickly summarize, running at any speed on the AirRunner will burn more calories than the equivalent speed on an electric treadmill. If you want to burn calories as quickly as possible, the AirRunner is literally the perfect machine to do so.

3) Less likely to require servicing – The AirRunner comes with a 150 000 mile warranty (241 401 km). That’s longer than the standard mileage warranty offered on most cars!

Of course something could go wrong with the belt, but you will be covered by the warranty unless you plan on running more miles than Mo Farah over the next 20 years. The biggest concern here is actually the connection with the computer/console that displays your speed, calorie and distance stats. The good news is that if you were to experience such a problem, it would be a relatively minor fix.

Also, it is worth noting that the motor is arguably the most important element of an electric treadmill and it is also the most likely element to breakdown after years of use. The AirRunner doesn’t have a motor, so you can rule out one of the biggest concerns when buying a normal treadmill.

4) You do all of the work – In this regard, a curved treadmill is a lot more like running outdoors. The moment you strop driving the treadmill belt forward it will come to rest quickly and naturally. The benefit of this is that it engages your hamstrings, glutes and posterior chain more effectively than an electric treadmill.

5) Improved Gait Mechanics – In essence, running on a curved treadmill facilitates a more natural gait pattern, without putting excess pressure on your calves. This is backed up by Mike Reinolds, a highly qualified physiotherapist and the owner of Champion fitness, and it is also supported by Chris Hinshaw, a highly qualified endurance fitness expert.

6) Better for improving V02 Max – To increase your V02 max, you basically need to engage in superfast endurance training intervals. 5x 800m at 90% of your max speed would be a good example. The Assault AirRunner is perfectly designed for this style of training. If the primary goal of your training is to improve your V02 max, you won’t find a training device more suited to the task than the Assault AirRunner.

So what are the drawbacks of the Assault AirRunner Treadmill?

1) It’s a lot more difficult to hit distance targets – If you like running 5km’s during your training runs, you will either need to get much fitter, or you will need to select a shorter distance. This is because you will expend up to 30% more energy when running any distance on the AirRunner.

2) It’s a bit like running up a really smooth hill – Even though this isn’t technically a downfall, it’s the biggest turn off for most runners. Why? Because most runners live in fear of hills. Admittedly, I’ve also found myself opting for an electric treadmill rather than a curved treadmill on occasion, because my ego always takes a small knock when I step onto the AirRunner.

3) It’s not as easy to gauge your performance on the AirRunner – This is where electric treadmills pip the AirRunner (and other curved treadmills). Running on a standard electric treadmill at 1% gradient is the closest you can come to running outdoors.

There have been plenty of studies into this. All of them suggest that when you set a standard treadmill to a 1% gradient, the oxygen consumption needed to run at a particular speed matches up with the oxygen consumption needed to run the same speed outdoors.

With the AirRunner, you can use up to 30% more oxygen when running at a given speed. This is great for improving your cardiovascular fitness and your V02 max, but it makes it harder to assess your training performance, especially if you are preparing for an upcoming race.

Is it true that you burn more calories on a curved treadmill?

Most manufacturers (including Assault) suggest that curved treadmills can boost your calorie expenditure by up to 30%. Before writing this article, I wasn’t entirely convinced by this number, after doing a bit more research, I was surprised to find that there are actually studies out there which back up the data.

For instance, there was a study put together by James M. Smoliga, Eric J. Hegedus and Kevin R. Ford. They set out to determine whether exercise performed on a curved treadmill provides greater physiological stimulus than exercise performed on a motorized treadmill. This is the conclusion that they came to:

“Curved treadmills elicit greater physiological stimulus than standard motorized treadmills with small, though statistically significant changes in the rate of perceived exertion at matched speeds”.

They are not the only sports scientists to put together a sophisticated investigation. The University of Essex created their own study, using 13 well trained male runners. Their conclusions also appear to backup what most curved treadmill manufacturers are saying. Here are the quick results of the study:

Significantly higher relative oxygen uptake across all velocities (32.5% increase)
Significantly higher heart rates during training (16.8% increase)
Faster running cadence (2.6% increase)
Higher rate of perceived exertion (27.2%)
Less efficient running economy (38.4% variance)

Now you might be wondering about that last point (less efficient running economy). Basically, it means that the runners had to use 38.4% more fuel/oxygen/energy in order to maintain a particular speed on a curved treadmill. Again, this actually confirms what the manufacturers are saying.

In the end, it’s safe to say that you do burn a lot more calories on a curved treadmill, and this can be up to 30% higher than running the same speed on an electric treadmill.

Testing The Calorie Count On a 5K Run

On the left, you can see the Garmin Forerunner 35’s interpretation of the run.

On the right, you can see my actual performance on the Assault AirRunner. There are a few things to note.

The calorie count on the Forerunner 35 (462) was actually higher than the calorie count on the AirRunner (405).
I found the run pretty difficult, and my pace was only 4.55 mins/km. On the road, I can run at 4.00 mins/km quite comfortably. This demonstrates how much tougher it is to run on the AirRunner.
It isn’t clear to me if you can insert your weight into the AirRunner’s computer console. User weight is hugely important when calculating the total calorie burn, so I need to do some more investigation into this.

Beware of the 20% Rule

The key to running on a curved treadmill without suffering an ego driven panic attack is to keep the 20% rule in mind. The 20% rule basically means that everything you do on a curved treadmill is about 20% more difficult than it would be on a standard treadmill set at 1% gradient. So:

If you usually run at 7mp/h, it would be best to run at 5.6mp/h on the AirRunner if you want to simulate the speed that you are familiar with
If you usually run 4 miles during your training, it would be better to run 3.2 miles on the AirRunner, if you want to simulate the distance that you usually run

The 20% rule originates from the Dr Patrick P.J.M Schoemakers, who conducted the University of Essex study into energy expenditure on a curved treadmill. Understanding the 20% rule is vital if you want to use the AirRunner for distance training.

Final Thoughts

The Assault AirRunner is a well-manufactured curved treadmill that excels at interval training, speed training and short distance endurance training.

The 150 000 mile treadmill belt is extremely reassuring, and it is safe to say that it will outlast just about any electric treadmill available on the market.

If you’re thinking about buying the AirRunner, it all boils down to this.

If you want a device that will help you burn a huge amount of calories in a short period of time, the AirRunner is an excellent choice. You really can push your body to its upper limits on this machine, and you don’t have to worry about mechanical failures.

However, if you are a long distance runner and you want a machine that can simulate outdoor running, you would be better served by a high quality electric treadmill with a solid warranty.