Curved Manual Treadmill with Zwift

Hi, I’m starting to look at getting a treadmill for home. I’ve come across a few different types but one that seemed interesting was the curved manual treadmill. They seem to be very expensive for no motor and less fancy dashboard etc.

So my question is … has anyone used a Curved Manual Treadmill?

One brand that was expnsive but well presented was the ASSAULT FITNESS AirRunner, seems popular in crossfit world.They claim that running on this machine feels as closer to real running.

Of course a footpod would be required for most tradmills if they are not a smart.

Thanks in advance.


I am a long time owner of a AirRunner, and I absolutely love the treadmill. I bought a treadmill out of necessity due to kids, and now using it for about a year, I could never go back to an electric treadmill. I love running barefoot, or with 5fingers. The instant speed changes to your running cadence is game changing/amazing. If you can afford it, and you enjoy treadmill running, buy it! As an added benefit, my 4yr old can run on it too…seriously he loves it (I can’t imagine my kid on a electric treadmill!!!)

Now as a brand new user to Zwift, I’ve been toying with foot pods and the Runn device. The Runn device does NOT work well with manual treadmills. Today i just found out I could pair the AirRunner’s controls directly with Zwift over Bluetooth! I did a test run and it worked fine; no need for extra devices!!! Going to gear up this week and try Zwift running with the AirRunner and see how it works out.

Happy to answer any questions.


Ps. The other nice thing about the AirRunner, it’s moveable (with a little muscle), so you can roll it outdoors if the weather permits

Here is pairing instructions for AirRunner and Zwift

Thanks Matt, appreciate your comments. How do you find doing 8 or 16 milers on manual? I think I’ve read these curved treadmill are difficult to run on for longer distances.

The curved manual treadmill I’m considering does not transmit Bluetooth or ANT so need to look into using a foot pod (or perhaps Wahoo tickr X) to connect speed to Zwift.

I’ve contacted Stryd and to my surprise they don’t support manual treadmills at this time! "Currently, Stryd foot pod is not compatible with manual treadmills due to the way that they move in regards to the motion of the foot. "

My other options are Garmin HRM-RUN or Garmin Foot Pod (older on shoe version). Both of which I already own. Only problem is I don’t have access to a curved treadmill in Melbourne, AUS to test on). So a $4000-$7000 gamble.


What issues have you found with the NPE Runn, I’ve been using mine other than reporting too high of a cadance it’s working great on my curved manual treadmill?

I’ve have stickers every foot and you can see the difference in the “power” performance of each leg and a slight speed up/slow down as clearly I can’t pace that well

Hi Matt,

I just read about the NPE RUNN device about 30 mins ago.

So with your experience you use the RUNN on your curved manual treadmill successfully?
Which curved manual treadmill do you have?
What doing 8 or 16 milers on your manual treadmill any form issues etc?

Hey Peter,

I’ve used stryd (really does not work well, though one user said times weight and height by 1.2 and update and it works but did not try myself) so ended up getting a NPE runn, I’ve not had any real issues other than the cadence is too high and has me about 30 steps per min too high.

It pairs with my Apple TV fine with no issues, the pace is where I expect it to be mainly due to its 30% more energy aka slower, I have the stickers just over every foot in the middle of each slant so I don’t get any wild jumps in pace. I also have a polar oh1 for heart rate paired.

I think the longest I’ve run is 75 minutes not because it’s difficult but I get bored on treadmills, it’s no difference to if I was using a powered one for my boredom level.

If my form is getting worst I find it easier to tell than on a powered treadmill, as it feels sloppy and harder/more effort when running. It’s not the same as outside but i find it near to outside than on an automatic one.

The only sobering thought is more of an ego issue as the curved self powered uses more energy and therefore your pace will be slower, so a 4min per km is more like 5min per km, but as I run by time, effort or heart rate I’m not that worried, just looking at the screen it says slower. Which I guess it why some people may say there could be an issue?

Depending on your fitness level and pace you try to run will determine how difficult you find running longer distances/time.

My recommendation is run by effort or heart for long runs and run intervals as hard as you like, the treadmill will slow down with your legs unlike an automatic treadmill, and you should not have any issues, if you run at your outside pace you will struggle, think as if you are running uphill!

I have a titanium strength curved self powered treadmill mainly because it was cheaper than the assault fitness air runner by £1k at the time which I was looking to buy, I’m sure it’s not as good as £10k Woodway.

Great response. Lots of details very helpful. Much appreciated.

Yes I’m also looking at the Titanium Strength Self Powered Curved Treadmill but in Australia’s it been re-branded. Still similar cost to yours from my research. Still a crazy price for a manual treadmill. Huge investment.

How do you think maintenance will be for your treadmill. eg: Replace/lube bearings or replace tread.

You get bored running, are you using Zwift for your runs?

I never get bored riding my Wahoo Kickr on Zwift for a few hours. Currently I use the NPE CABLE device to consolidate my Bluetooth signals for Apple TV. My main reason to get a treadmill is to use it with Zwift. Also family might use it potentially.

At this stage I plan to use Apple TV running Zwift app. A NPE Runn with a 4iii heart rate strap. I’ll be interested to see if my Garmin HRM-TRI strap will provide metrics like it does outside.

Hi Peter,

They are crazy expensive consider a normal treadmill 80% of the cost is the motor these don’t have one!

I’ve taken the side off to inspect the bearings (and refitted the sides) but I’ve not done any maintenance other than to clean the slants.

I should mention I’ve always ran out doors so running inside is a bit strange, I also have a spin bike but bored doing that too, rather than outdoor cycling, I don’t think it would be an issue for you.

Yep using zwift while running and it works would I just wish there was a better “map” to show all the possible routes and ones I’ve not run before.

Your setup is simple but I don’t have a cable or wasp for the Garmin HRM-tri so optical polar oh1 gets used.

You will certainly enjoy running on a curved self power treadmill plus I think it’s just safer as you are in full control, just don’t look at the pace and go be your effort.

Hi again,

What position did you setup the Runn? Instructions mention a flat area and there does not seem to be much flat on the sides or does that not matter.

Also what is the Running Surface Height? 10 or 13 inch?


Hi Peter,

I messaged north polar engineering about the positioning and they said the base results are on a flat surfaces but if there isn’t a suitable location then pick somewhere it will not be knocked.

I choose the right hand side at the front of the trendmill just in forward of where foot would strike.

It’s 13 inches in the middle of treadmill and photo below on its placement image

Great information again. I would put it in the same position. Well it’s almost decision time!!

I came across a video by plantED on youtube PlantEd Review Curved Runner Video []). Similar to your previous observations, he said on the curved Air Runner he has found that the per mile pace on this treadmill does not translate to his per mile pace on the road. He thought the difference is probably in the 1 to 2 minute range depending on the runner. For example, a 10-minute mile on the AirRuner is probably a 8-9 minute mile on the road. There’s an article in The Journal of Science and Medicine in Sport that said “not only did runners work 30 per cent harder on curved, non-motorised treadmills, but they felt it, too. Their perceived efforts “matched the physiological data…32 per cent more oxygen uptake, 16 per cent higher heart rate and a 2.5 per cent increase in cadence.”

My Wahoo Tickr X arrived today for future use/testing. I’ve took a mini plunge and ordered the NPE Runn (for future use) a few days ago, from the USA (I live in Melbourne). One or the other I’ll need it. I’m thinking if I get a treadmill it will not be smart so will need the Runn anyway.

I finally received a response from Zwift in regards to the Runn. Their response was…

I see you’re interested in using a NPE Runn device on your curved manual treadmill. I’ll be happy to help! The NPE Runn is not designed for us on a manual treadmill however there is nothing stating you can’t use it. people have tried and it did not work while others have had success with it. Take a look at the Zwift Forms​ and you will see what I am talking about! If you do desire to use Zwift, I would like to suggest getting a Zwift RunPod​ as it has nothing to do with the treadmill itself.

Hi Peter,

I would agree it’s certainly more difficult on a curved self powered manual treadmill, think the effort to run up a hill vs running on the flat, if you want to run the same pace, you need more effort, if you want to run the same effort you have a slower pace, 25%-35% differences is about right.

I know some people have had issues with the NPE runn, lack of cadence and pace is out, update the firmware when you get the runn as that resolves a potential issues, the others I believe are treadmill speed vs run speed being out, tricky as either or both be wrong. I know their were some issues with labels you place on the belt that fall off and others had text on their belt which were being read that caused issues.

When I was messaging Tim from NPE about the run, these were his responses.

“ Yes, the Runn should mount fine and work fine with a curved, self powered treadmill. One of our developers actually tested with a Technogym curved treadmill recently and it worked fine.

For cadence, we have an onboard circuit that is looking at motion data. The motion data is run through an algorithm which provides cadence.

The maximum speed is limited by the values that will fitness in the speed data sent over Bluetooth. This limit is 655.31 KM/H or roughly 407mph.”


“I would suggest wherever it is most out of the way for you. Since you don’t really have an incline, the angle it’s mounted on isn’t super important.”

The footpod (formerly milestone) I believe has the same issues as all footpods, from the calibration pace it’s accuracy decrease, stryd is the best in the game and they have issues, you maybe find the footpod issues tracks differently in your faster interval and easy recovery paces, calibrate it for the steady place you will run to get the best results.

Also check out DC rainmaker review on the NPE Runn if you have not already done so and read the comments, would give you a good overview of any potential challenges

One thing to check whether the footpod is correctly providing the speed is to change the calibration to something stupid like 1.5 or 0.5 as the pace will be silly fast it as painful slow. Not sure if you can do it on the app to send to the pod or just on a watch and broadcast to zwift

Yes I’ve spend many hours searching the internet for anything curved manual treadmill related. I’ve been following DC Rainmaker for many years now and have read his review and ALL the comments. It’s a pity I can;t try a curved treadmill. If this COVID19 saga was not happening I may have a chance to get a demo somewhere. I think in relation to product maturity and community penetration it’s early days. Who knows in years to come it may be the only option or something else will be a game changer, pity it’s so expensive. No doubt it does deliver results.

Anyway I’m certainly armed with lots of information now. I like to thank you especially for your wonderful feedback Matt. All of the companies I’ve reached out to have responded. Garmin, Zwift, Wahoo, NPE, Stryd etc. as well as anyone who has posted on various forums and the also the fitness Influencers.

Here’s some useful information for everyone on this thread:
For those concerned about having proper metrics. I was able to adjust the distance calibration in ismoothrun and make Stryd weight adjustments for the Air Runner to align power, pace, time and distance. This is all using the Apple Watch Series 5 LTE ecosystem, ismoothrun and syncing data to Powercenter via Garmin Connect. What this means is you will be able to have proper metrics all aligned!

After 3 x 1 mile tests I’ve found:

1 mile Air Runner = 0.85 miles on Stryd non wind (uncalibrated). No incline adjustment

1mile / 0.85mile =
ismoothrun app setting distance calibration factor = 1.176 (Settings/Sensors/BT Smart Sensors/Stryd)

Weight calibration on Stryd iPhone app = Weight x 1.25
*1.25 Power adjustment factor may change based on an official CP test

147lbs x 1.25 = 183.75 (rounded up to 184 lbs)
iPhone app (Settings/Stryd/Update Height and Weight)

Based on these findings (before doing a thorough CP test on the Air Runner) as well as looking at RE factors that notes Power calibrates RPE and RPE regulates Power-- I have aligned Power, Pace, Time and Distance all together to work on the Non Motorized Air Runner Treadmill.

My steps:

  1. Make sure Garmin Connect is linked to Powercenter.
  2. Adjust my weight for the Stryd (non wind) pod in the iPhone app to 184lbs.
  3. Set the distance calibration on ismoothrun to 1.176
  4. Use the Apple Watch to start treadmill workout in order to get HR data saved. if you use the iPhone app it won’t save HR data.

Now pace and power are calibrated on the Air Runner console and ismoothrun. This is also true for Time, Distance, Power and Pace. They are all giving me the same numbers. Once the workout is done it will sync to Powercenter via Garmin Connect automatically. (ismoothrun doesn’t have a direct export to Powercenter).

**Power on the Air Runner console is not correct, nor has it ever been close to Stryd. I still need to contact Air Runner and find out what they are doing with their Power metric. It’s way way too high. What is it based on?

I’ve been cycling on Zwift for almost five years, using a Tacx Neo or Assioma Duo pedals as my power meter.

In January this year I bought the Assault Air Runner and use a Stryd non-wind footpod on the treadmill. I read the article about increasing weight by 20% for the treadmill and that seems to produce power figures which compare well with the bike for equivalent heart rate and perceived exertion. It also has my critical power in the same ballpark as my FTP, so overall I’m happy with this solution.

As for pace, this is depressing, because it is undoubtedly slower compared to flat road for the same effort/power/HR. I have not tried to compensate and I just suck it up, accepting that I get short changed in Zwift for my actual speed/distance, were I to be running on the flat. Stryd and the treadmill are close on speed/distance, but not a perfect match. Differences are not enough to trouble me as an amateur who is more interested in keeping fit than competing.

As for power readings on the treadmill, yes, they are massively elevated compared to Stryd and my bike power meters. 200W from Stryd shows as 600+ Watts on the treadmill. I did contact Assault Fitness, but rather than explain it they said it might need calibrating. That would be one ■■■■ of a calibration. At least calorie count is broadly in line with what my Garmin produces so my guess is that the treadmill shows gross power for the entire body (with all the waste heat and flailing arms etc.) whereas Stryd, like the bike power meter, shows only the net power of useful work at the soles of the feet.

Addendum : I actually find Zwift running to be a dull experience, but using power from Stryd I find it far more satisfying to join a group RIDE on Zwift with suitable power targets rather than plodding along with an under reported pace. With power well matched to the bike experience I think it’s a fair exchange.

Hi guys. I own a Assault Air Runner as well but I’m not being able to connect via PC App. Only with Iphone App. Did you guys have the same experience? I can find the Air Runner on Windows Bluetooth Configurations screen and could even pair but when I open the Zwift app on my PC, it never recognize the treadmill… keeps only seaching…

Hi, I am able to pair it with my pc. I am using an usb extension to reduce the distance to about 6 feet from air runner console to blueetooth receiver.

It still take more time to find the signal than on ipad/iphone. my polar heart strap is found almost instantly in comparision.

Remember that Bluetooth only works with connecting to one device at a time, so make sure the treadmill is not connected to something else first if you want to use the PC.

Since I use Stryd I haven’t worried about connectivity from the treadmill, but I tried it today and it worked just fine. Note that (I think) you have to press the Bluetooth button on the treadmill to start transmission. I’m not sure that it wakes up simply from starting the treadmill. Maybe that is just for initial pairing though. Not sure.

Either way, I got my avatar to move just fine from the treadmill Bluetooth, without even wearing my Stryd. For the photo I’m having to hold the Windows laptop and the phone whilst walking on the treadmill so 4kph is all I can manage, but you’ll see it matches in Zwift and on the treadmill display.