We can tell you how good curved treadmills are, but the truth is, you’ll really appreciate curved treadmills once you use one. However, in this article, we’ll do my best to go over their benefits, how they work, what muscles they target, and most importantly, what makes them very different from motorized treadmills.
We’ll list all the pros & cons of curved treadmills. We won’t skip the drawbacks and also explain why they are so darn expensive. We’ve comparted curved treadmills head to head with regular motorized treadmills.
It doesn’t matter whether you want to lose weight, do HIIT, or just want to get a good cardio workout.
You’ll learn why curved treadmills are more effective than electric treadmills in almost all aspects.
We’ve even included a whole section with references to studies proving that curved treadmills actually work.
If you’re trying to decide which curved treadmill to buy or whether a curved treadmill is right for you, this article will tell you all the good and the bad that you must know before a costly decision.
Finally, if you decide to buy a curved treadmill, we’ve included a rundown of the best curved treadmills you can get in 2021.
- How Curved Treadmills Work
- Walking & Running on a Curved Treadmill
- Curved Treadmills vs. Motorized Treadmills
- Benefits of Curved Treadmills
- The Downsides of Curved Treadmills
- Curved Treadmill for Home Gyms
- Best Curved Treadmills
- Assault AirRunner
- IN10CT Health Runner
- SpeedFit Speedboard ProXL
- Sprintbok Curved Treadmill
- Resolve Reactive Runner
- Woodway Curve
- Technogym Skillmill Treadmill
- Cheapest Curved Treadmill
- Why Are Curved Treadmills So Expensive?
- Used Curved Treadmills
- Curved vs. Standard Treadmills for HIIT
- Proofs that Curved Treadmills Work
- The 10 Step Curved Treadmill Workout
HOW CURVED TREADMILLS WORK AND WHY YOU SHOULD CARE
Curved treadmills are manual machines that have no motor and need no electricity. The treadmill belt is powered by your energy and nothing else. When the balls of your feet strike the belt, instead of pushing your body forward, your feet push the belt backward behind you. Your body remains stationary, centered on the treadmill.
The brilliant idea that makes these treadmills work lies in that curved running surface. Your forward foot hits the belt near the top of the inverse half circle. This makes it easier for each foot strike to propel the belt backward down a gently curved slope than if the belt were flat or even inclined.
Because of its curved surface, the running belt is made of a series of slats rather than the continuous long belt surface of regular treadmills. Each slat is separated from its neighbors by tiny gaps. These allow the belt as a whole to move smoothly around the arc.
Curved manual treadmills go as fast as you go, which feels more natural than the fixed speeds of motorized treadmills. You’ll also feel less impact on your joints with each step because the curve comes up to meet your feet at the front of your stride. That’s actually a significant advantage curved treadmills have over flat electric treadmills, but one that is often overlooked.
Curved treadmills have fewer moving parts than regular treadmills, and the fact they have no motor means one less thing that can go wrong. They’re also completely green, so you won’t have to worry about finding a plug or racking up a massive electric bill.
Some of these machines have a high weight capacity of 400 lbs or more, so like other heavy duty treadmills, they are great for heavy people.
WALKING & RUNNING ON A CURVED TREADMILL
Most curved treadmills allow you to walk, run and sprint. You might feel a bit off balance when you first get on the kidney-shaped track, but if you push through, you’ll quickly get your bearings.
The secret behind the mechanics in these machines is a combination of friction, gravity, and your natural stride. With every step you take, either running or walking, your point of contact with the track is ahead of its center of mass. That means your body weight transferred through your foot is enough to pull the tread from the top of the curve down and back toward its center of mass at the bottom of the curve.
As your foot moves backward past the center, the curve briefly follows the natural upward motion of your foot. Since your stride both begins and ends at the ergonomic edge of a natural arc, it encourages you to run on the balls of your feet and push off with your toes. This is a more natural way to run and encourages correct posture.
You can expect a bit of a learning curve when learning to run on this curve. Pushing a belt behind you feels a bit different than pushing yourself forward on the ground. It’s easier if you keep your core engaged.
You’ll need to practice accelerating, decelerating, and running at a steady pace. The arc helps with acceleration and deceleration. You can run faster by moving slightly forward toward the front of the arc or slower by moving slightly backward.
You’ll probably need to hold onto the handles at first to help keep your body steady as your feet learn to push the belt. Once you figure out your balance enough to let go of the handles, you should pump your arms as you run to help you keep up your momentum.
Once you feel steady enough to try sprinting, you’ll find it’s much quicker to get up to full speed on a manual treadmill than waiting for a motorized treadmill to power up. If you want to stop, you don’t have to press any buttons or pull any emergency cord. Just stop moving your legs, and the belt will stop with them.
CURVED TREADMILLS VS. MOTORIZED TREADMILLS
Doing a cardio workout on a curved treadmill is more effective than a workout on a standard treadmill.
Here are 7 reasons why
- Burns More Calories – According to multiple studies that we’ll talk about later, curved treadmills burn about 30% more calories than motorized treadmills. The growing body of research comparing exercise on a regular treadmill to exercise on a curved manual treadmill indicates that the latter uses a lot more energy.
- Higher Heart Rate – Studies show the average heart rate when running on a curved treadmill is about 16% higher than on a motorized treadmill.
- Higher Oxygen Consumption – Your VO2 max measures how much oxygen you consume during exercise. Researchers consistently found that athletes’ VO2 max on a curved treadmill is about 32% greater than running at the same speed on a flat treadmill.
- More Intense Workouts – Researchers using the Borg Scale to measure perceived exertion found curved treadmill running to be about one and a half units more physiologically intense than on a flat treadmill.
- Ideal for HIIT and Sprints – Curved treadmills let you accelerate super fast and reach a higher top speed almost instantly, so you can push yourself really harder. That’s only the first part, as HIIT workouts and sprints also require you to slow down fast. Slowing down with a curved treadmill is as natural and quick as slowing down running outdoor. Regular treadmills are very bad as slowing down quickly. When you are running at a crazy high speed, sometimes to exhaustion, you just don’t air or power left in you to wait for a motorized treadmill to slow down so fast, let alone the coordination to press the speed deceleration button on the panel. The curved treadmill is the perfect cardio machine for doing a home HIIT cardio workout. All these factors work together to make curved treadmills a perfect storm for HIIT and sprints.
- Works More Muscle Groups – Traditional treadmills move the floor under you. That means your legs just have to push up off the ground instead of fully activating. Curved treadmills make you do all the work, which uses more muscle groups. This action hits your glutes, calves, and hamstrings hard. It also activates your entire posterior chain and all your stabilizing muscles.
- Less Joint Pain – The curve comes up to meet your foot at the beginning of the motion. Together with the cushioned rubber surface, this translates to much less impact on your knees, ankles, hips, and back. Less pounding of the ground means less shock, less wear and tear over time, and fewer injuries.
- Improves your Form – Curved treadmills promote an upright running posture and correct mechanics. They make it easier to run on the balls of your feet like a true athlete, which can give you more speed and agility in the real world.
BENEFITS OF CURVED TREADMILLS
- Safer – Curved treadmills stop when you stop, so there’s less danger of falling and getting thrown. Their running decks tend to have more grip than the PVC, nylon, or cotton-based belts of motorized treadmills. More grip makes the belt easier to push, but it also makes it harder to slip off. Curved treadmills are also less of a fire hazard because they don’t have motorized parts that generate a lot of heat or friction.
- No Electricity Cost – Curved treadmills don’t use electricity and won’t add a dime to your electric bill. You won’t have to look for an electrical outlet to place your machine by or get tangled up in miles of extension cords.
- Environmentally Friendly – No electricity means zero carbon footprint.
- Simple to Use – Curved treadmills have minimal to no buttons. You don’t have to figure out any software or wait for the machine to power up. Just jump on, and take off.
- Less Maintenance – Because they have no motorized parts, curved treadmills are low-maintenance machines. Their non-motorized slatted belts are much more durable than traditional treadmill belts. They won’t need constant adjustment or lubrication.
- Intuitive With No Need for Programmed Workouts – With a curved treadmill, you don’t have to rely on programmed workouts. You can adjust your speed instantly depending on how you feel. You can start or stop without thinking and just go with the flow without fiddling around with beeps and buttons.
THE DOWNSIDES OF OF CURVED TREADMILLS
- Expensive – The main drawback to owning a curved treadmill is the price. Right now, curved treadmills are much more expensive than most other workout machines.
- Big – Regular-sized curved treadmills tend to be bigger than regular-sized flat-belt treadmills. You can find compact curved treadmills, but they also tend to have a larger floor footprint than compact flat-belt treadmills.
- Doesn’t Fold – We haven’t seen any foldable curved models yet. If you don’t have a dedicated space for placing the machine and want to use the same area for work or study, you may have to get a foldable flat-belt treadmill. You can it folded and unfold only when needed.
- Less Ideal for Leisurely Runs – If you like going on long, slow runs where you let your mind drift off as your body does its thing, a curved treadmill may disappoint you. Even just walking is a little bit harder on a curved treadmill than on a flat motorized one
- Barebones – Besides the magical mechanical manual belt technology, curved treadmills can be pretty bare bones. Most don’t have extra features like speakers, fans, USB chargers, and Bluetooth. Many models don’t even have a screen. The ones that do usually have a basic console with minimal workout data. If you like giant colorful screens that take you on scenic programmed workouts through beautiful locations, you might prefer a traditional treadmill.
CURVED TREADMILL FOR YOUR HOME GYM
Curved treadmills are beginning to catch on in the gym scene. Most commercial gyms still use standard electric treadmills, but we’re starting to see more and more gyms bringing in a curved treadmill or two.
We believe a curved treadmill is one of the best pieces of cardio equipment you can buy for your home gym as well. The two major downsides are that they’re expensive and that they aren’t exactly the most compact cardio equipment. They can take up a lot of space on your floor, and there aren’t any folding models yet.
If you love intense exercise and cutting-edge technology, we think the benefits of having a curved treadmill in your home gym outweigh the drawbacks.
BEST CURVED TREADMILLS
The Assault AirRunner is the most popular curved treadmill for individuals and home gyms. The AirRunner was also our favorite overall pick when we reviewed the top manual treadmills. Designed with athletes in mind, it has smooth mechanics that let you accelerate fast. Customers say the tread is comfortable and forgiving.
This model has more extra features than most others. The small screen has a prettier interface than many other curved treadmills. It even comes with Bluetooth.
The AirRunner uses about the same floor space as a single bed. It’s the lightest model on our list, weighing only 280 pounds, making it easier to move around than the others. The running track has a higher-than-usual peak of 18 inches. That means you’ll need a ceiling that’s at least 20 inches taller than you.
It comes with a five-year warranty for the frame and three years for the other components. For more details, you can also check our full review of the Assault AirRunner.
IN10CT Health Runner
IN10CT’s Health Runner is an excellent option for larger people on a smaller budget. With a 400-pound maximum user weight, it’s the cheapest high weight capacity machine on our list. The other heavyweight curved treadmills we like cost much more.
The curve on this treadmill is just a bit less intense than the other models on this list, which makes running slightly easier. If extra weight or age makes it hard for you to lift your legs high, you’ll appreciate the gentler curve.
To compensate for the gradual curve, the IN10CT Health Runner comes with a special dual-bearing system. It cuts the friction even more than usual and makes the track more responsive to your movements. Less friction means it’s even easier to get the belt started and easy to transition between walking, running, sprinting, and stopping.
The belt’s slats are made of a steel skeleton covered with half an inch of rubber coating. If you suffer from joint pain, a rubberized model like this one will cushion you much better than one with hard plastic slats. You’ll probably want to wear shoes, though. Rubber-coated slats will turn your feet black if you run barefoot.
SpeedFit Speedboard ProXL
The ProXL also has a massive 400-pound maximum weight capacity for running. On top of that, this curved treadmill has an 800-pound weight capacity for walking only. So it’s 400 lbs for running and 800 lbs for walking. That makes it a great option if you weigh much more than you’d like and want to get started on the road to better health with some intense walking.
This machine has a lot of thought put into its shock absorption and is proud of it. Each slat is topped with an elastic fiberglass mix placed over a layer of rubber. This clever combination is designed to absorb most of your impact energy even if you’re a heavy person.
If you like personalized workouts, the ProXL has 5,000 of them. Although we love curved treadmills for their you-powered motivation, sometimes it’s nice to put your mind down and let a program tell you what to do.
When you turn on the machine’s LCD, it will get you started with a quick questionnaire. The process takes about 10 minutes and helps the program get a better idea of your body and goals so it can recommend you the right workouts.
Speedboard’s ProXL has an extra-long frame warranty of 10 years to give you peace of mind. The belt is also guaranteed for five years. Read our Speedboard review to learn about the other features of this treadmill.
Sprintbok Curved Treadmill
NOHrD’s curved treadmill, the Sprintbok, has to be seen to be believed. The smooth, sleek frame is made of rich hardwood with the grain patterns intact. It looks like something you might find in a bamboo forest at a yoga retreat in Bali.
Besides the aesthetic beauty, the wooden frame also has a functional purpose. It absorbs vibrations much better than steel and other metals. This helps make the Sprintbok quieter and more stable when your feet are giving it a pounding. The slats are wooden as well, but they come with a linoleum finish for shock absorption.
To go with its picturesque motif, the Sprintbok comes with a giant LCD screen that measures 17 inches across. This is much bigger than the screens on most similar models.
Not only does the screen show your stats, it’s one of the few curved treadmill displays that can take you on pre-programmed runs through scenic locations. If you like following along with a human instructor while you run on the beach or through the streets of Paris, you’ll fall in love with the Sprintbok.
The manufacturer advertises this trainer as a maintenance-free machine thanks to its high-quality source materials. You’ll still have to give it a regular dusting, but you won’t have to tighten the belt or grease up any internal parts.
With all those praises you might wonder what’s not to like about the NOHrD Sprintbok? Well, the only major downside of this treadmill, while it’s one of the best curved treadmills out there, it’s also one of the most expensive.
Resolve Reactive Runner
If you like running with resistance, the Resolve Reactive Runner has four levels of magnetic resistance. The lowest level is great for heavy-duty walking, the middle levels feel like you’re running up a hill, and the highest level is designed for sled pushing.
You probably won’t be able to run at the highest resistance level using just your body weight. You’ll need to lean forward, grab the handlebars and push hard with your feet. Sled pushing lets you use this trainer to get in some upper body work as well.
The handlebars are designed ergonomically to give you plenty of comfortable grips. They’re also strong enough for you to do dips if you want to tone your triceps between runs.
Weighing almost 400 lbs, the Reactive Runner is tied for heaviest with the Technogym Skillmill (reviewed later). To keep the superlatives going, it’s also tied with the Skillmill for the broadest running surface at 19 inches.
The Resolve Reactive Runner comes with a 6-inch backlit LCD screen that tracks your stats. The device comes with three preset HIIT programs to help you get started.
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The Woodway Curve is proud of being the first curved treadmill that all the others are based on. Its original design dates back to 1974. It’s still used by plenty of professional athletes and many rehabilitation. It’s also a popular option for people who have a home gym setup, as well as a stand-alone machine for doing cardio at home.
Their drive system boasts over 100 ball bearings. These help your feet push the belt around its track almost completely friction-free.
It’s so smooth that it borders on being slippery, so make sure you practice your stride balance and foot placement before letting go of the handles. The extra smoothness makes acceleration and deceleration easier, but the track can feel a bit unstable at first, especially at high speeds. You’ll need to give your legs and feet time to adjust before trying to sprint on this machine.
The frame is made from steel, and the guide pulleys are precisely calibrated to the belt. Users say the mechanics are pretty durable, and the high weight capacity backs them up. This is another curved treadmill with a 400-pound capacity for running and an 800-pound capacity for walking.
At 67 inches long, this commercial machine has the longest running surface. If you have very long legs, you’ll enjoy the extra inches of striding space.
Technogym Skillmill Treadmill
The Skillmill is a curved treadmill designed for commercial gyms. It’s the most expensive machine on our list, and at 180 kg (almost 400 lbs.) it’s also one of the heaviest.
It has the largest total running area of 66 inches long and 19 inches wide. If you tend to flail your arms when running, have wide hips, or just enjoy a spacious running belt, the Skillmill is both extra long and extra wide.
We love its convoluted handlebars that give you many ways to brace yourself for performing agility and strength exercises. The power handles work for sled, straight-arm, bent-arm and side pushes. The long parallel horizontal bars let you do high and low pushes and sideways stepping.
This machine is the only one on our list that also comes with removable rear handles and an accessory kit for even more upper-body exercises. The kit includes straps, individual handles, and a waist belt. These let you do all your favorite band-based exercises while facing forward or backward.
The Skillmill has 11 degrees of magnetic resistance that you control with a convenient push-pull lever. If you like to run hard, the curve on this model is a little steeper than usual. That means you’ll have to lift your legs a little higher, but it makes accelerating to sprinting speeds slightly quicker and easier.
The Technogym Skillmill might be an overkill for a home gym. If you don’t intend to use the machine for hours every single day, you might be better off buying one of the other curved treadmills we reviewed here, like the Assault AirRunner, Speedboard ProXL, Health Runner, or the Sprintbok.
CHEAPEST CURVED TREADMILL
The cheapest curved treadmill that we like is #6 on our list, the Resolve Reactive Runner. It still has a price tag in the thousands, but it costs a few hundred dollars less than the other cheaper models, the Assault AirRunner and the IN10CT Health Runner.
We found an even cheaper option, the TZ-3000C, listed only on Alibaba. The TZ-3000C is made and distributed by a Chinese company and costs under a thousand dollars. We weren’t able to find any reviews or information from people who have bought the TZ-3000C, only the marketing claims from the manufacturer.
Even though you might save a couple thousand dollars, we can’t vouch for the reliability of this machine or its distributors. It could end up being a great deal, but you also risk losing a lot of money or owning a big lemon. Buying clothes, electronics, or other cheap trinkets from Alibaba or AliExpress is a lot less risky than investing in a large, costly item from an unknown company with an unproven guarantee.
WHY ARE CURVED TREADMILLS SO EXPENSIVE?
Curved treadmills can seem unrealistically expensive for a one-note gym machine with no motor. A quality curved treadmill can be four or five times the price of a quality motorized treadmill.
The technology in both the design and the mechanics of a manual curved treadmill is still pretty new compared to regular motorized treadmills with a flat surface. New technologies that haven’t hit the mainstream yet tend to be more expensive. Manufacturers have to focus on recouping their investments.
Once curved treadmills catch fire and the demand grows, we believe the price will begin falling. Fitness equipment manufacturers will streamline their operations, parts will get cheaper, and there will be more competition between manufacturers of home cardio equipment.
New technology is always a bit of a rollercoaster at first. It may take a bit more time for curved treadmills to go viral, but prices do seem to get lower with time.
We believe curved treadmills are some of the best cardio machines out there. Do they justify their high price? We think yes, especially if you are after intense cardio workouts, sprints, HIIT, and like to break a sweat. If it weren’t for their price, we would recommend them over motorized to almost anyone.
USED CURVED TREADMILLS
Curved treadmills are still considered new technology, and it’s not easy to find used models for sale. Doing our research for this article, we were only able to find one or two used curved treadmills available, which is insane compared to the numerous used motorized treadmills you can find on eBay, Craiglist, or Amazon.
The ones we saw listed on trustworthy sites weren’t that much cheaper than the new models. The average price was about 60% to 70% the price of a new model, and the shipping costs are usually quite high for such a large and heavy item.
Woodway, the maker of the Woodway Curve, has a factory-certified pre-owned model program online that we imagine has deals on used curved treadmills. We weren’t able to check their prices because you have to get approved for the program before they show you what’s available.
The scarcity of used curved treadmills could be because they are relatively new on the market. It might also be because curved treadmill owners are so satisfied with their treadmills that very few want to resell them.
CURVED TREADMILLS vs. STANDARD TREADMILLS For High Intensity Interval Training
HIIT and sprinting involve fast-twitch muscle fibers. These are made for short, intense bursts of activity rather than long, slow endurance activities.
Manual curved treadmills are much better for sprinting and HIIT because they let you accelerate and decelerate faster and more precisely than motorized treadmills. You’ll sprint faster under your own power than the motor on a regular treadmill can turn, as you control the speed of your run just as you would running outside.
WHY STANDARD TREADMILLS ARE NOT GOOD FOR HIIT
On a standard treadmill, you have to fiddle with the buttons, wait for the machine to power up, and then think about matching speeds. All this extra attention isn’t helpful for routines that involve quick starts and stops.
It can even be dangerous to have to think about manually adjusting the motor’s velocity when your mind and body are wiped out. On a manual curved treadmill, when you want to get started, you can just jump on and run. When you want to stop, you can just stop, and the machine will stop with you.
PROOFS THAT CURVED TREADMILLS ROCK
BURN MORE CALORIES
We found a few studies comparing calorie-burning between running on a curved treadmill, a motorized treadmill, and on the ground. The studies used between 10 and 20 participants, males and females, of various ages and weights.
Researchers had participants walk on a curved treadmill, a motorized treadmill, and over a normal ground surface for around five to 10 minutes each. They then measured oxygen consumption and used it to indicate calorie expenditure. The formula the studies used equates about one liter of oxygen to five calories.
This 2011 study showed that participants burned around 30% more calories on the curved treadmill. (Link: )
A later study done in 2014 estimated participants were burning up to 44% more calories on the curved treadmill than on the other options.
HIGHER CARDIOMETABOLIC DEMANDS
This Australian study from 2017 involved 14 active male and female runners between 18 and 45 years old. It found that oxygen consumption and heart rate were much higher on a curved treadmill than running over ground or on a motorized treadmill.
Combining all the data from males and females at any speed showed the average heart rate was around 20 beats per minute faster on a curved treadmill. Oxygen consumption was also about 15% higher on the curved track.
As you might expect, researchers came to the conclusion that the higher cardiometabolic demand was probably due to the higher resistance of the curved manual belt, as you have to accelerate it yourself with each step. They also found that the less you weigh, the more difficult it will be for you to run on a curved treadmill and the more you’ll exert yourself.
HIGHER HEART RATE
This 2018 study by the University of Essex involved 13 male runners. It found that participants’ heart rates were around 16% higher when exercising on a curved treadmill. They also consumed about 32% percent more oxygen.
This 2018 study showed that a few short runs on a curved treadmill can help improve your running posture, balance, symmetry, and efficiency in the real world, not just while running on the treadmill.
Imbalanced running often leads to injury in athletes. The strides of the athletes in this study grew more balanced and symmetrical when they ran on a curved treadmill in short bursts.
Long strides usually mean more joint impact. Athletes reduced their strides slightly when running on a curved treadmill, keeping their feet more squarely underneath their center of mass without lowering their speed.
This slight stride reduction of about 6 – 8% made their running more efficient and used less hip and knee flexion. It also improved the angle between their legs and the ground at the moment of contact. Running with this slightly straighter angle decreased contact time, which increased running economy.
Researchers found that after only a few minutes on a curved treadmill, these improvements stuck with the athletes and continued to influence their gait patterns.
10 STEP CURVED TREADMILL WORKOUT
If you’re used to training on a flat-belt treadmill, you can do a similar routine on a curved treadmill. You can also add a few HIIT exercises and sprints if you’d like to spice things up.
Here’s an example of an all-purpose workout on a curved treadmill.
- To start with, you need to familiarize yourself with the curved surface and the unique way it moves. We recommend beginning by standing in the middle of the track and holding the handles firmly. Once you feel balanced, start strolling for one minute.
- Let go of the handles, and walk slowly for another minute.
- If you feel steady, try jogging for one minute.
- Let’s do some intervals. Jog in place for 30 seconds, and then run for the rest of the minute. Repeat two more times.
- Take a short break.
- Let’s do some sideways work. Face to one side, and hold on to the handlebar with both hands. Do 30 seconds of side steps, pushing the belt sideways with your feet. Feel free to go as slow as you need to.
- Turn to the other side, and do 30 seconds of side steps in the opposite direction.
- Now, we need some speed. Sprint on the treadmill for 30 seconds, and then rest for the rest of the minute. Repeat this interval two more times.
- Let’s end with some heavy pushing. If your treadmill has resistance, set it as high as possible. Lean forward, and brace your shoulders against the front handles. Do 30 seconds of sled pushing, and rest for 30 seconds. Repeat three times total.
- Cool down by walking for a few minutes as you bring your breathing and heart rate back down.