Today I want to talk to you about whether or not assault runners, self-propelled treadmills, and all those curved treadmills that you see in your gym or CrossFit box are actually harder than your traditional treadmill.
As you’ll see when I share my conditioning workouts, a lot of times I’m doing my training on an assault treadmill in my gym. A common question I get all the time is: “Is that thing actually harder than a regular treadmill or road running? Because man, it looks hard!”
I want to cover that today by going through several studies that have actually looked into this question. The short answer? Yes, they are significantly harder – and I’ve got the science to prove it.
There are basically two types of treadmills that you’ll see in exercise physiology labs and gyms: traditional motorized treadmills and the newer self-propelled or self-motorized treadmills.
Traditional Motorized Treadmills:
A regular treadmill uses a motorized belt, which means you’re forced to run at the speed you select. No matter what, you’re locked into whatever the treadmill is set to unless you personally decide to change it.
This is different from road or trail running where you can adjust your pace and auto-regulate based on how you feel, the intensity of the run, or the duration. Your pace may naturally oscillate throughout your run, which is pretty normal and natural.
Self-Propelled Treadmills:
With self-motorized treadmills, you are essentially the motor. You’re the one driving and moving the belt, which brings in your ability to self-regulate, pace, and control the speed because you yourself are powering the movement.
These treadmills are built on an arc with a slight uphill slant, so you’re running against that grade. The closer you run to the front, the faster it goes, and the further back you are, the slower you go. You have to stay toward the front of the treadmill to keep it moving, which requires constant effort.
Let me walk you through the key studies that have examined this question scientifically.
Study #1: Physiological and Perceptual Demands
The first study I want to highlight looked at “The physiological and perceptual demands of running on a curved non-motorized treadmill and the implications for self-paced training.”
This study examined 13 trained males through VO2 max tests and incremental exercise protocols on both traditional and self-propelled treadmills. One of the most important findings was that participants ran at the same speeds on both types of treadmills, which confirmed that any differences in physiological response were due to the treadmill type, not the intensity.
Key Findings:
Study #2: Walking and Running Comparison
Another study called “Increased physiological intensity during walking and running on a non-motorized curve treadmill” looked at 10 healthy athletic adults and found similar results. The amount of physiological effort required to sustain the same pace on self-motorized treadmills was significantly higher.
Study #3: 5K Performance
Two studies examined 5K performance on these treadmills versus motorized treadmills. Both found that 5K performance was significantly lower on curved treadmills – up to 24% slower for the same physiological effort.
There are several reasons why these treadmills are more challenging:
1. You’re the Motor
You’re forced to move the belt yourself, which requires additional energy expenditure beyond just running.
2. Constant Incline
The curved design means you’re always running on a slight grade, which increases the workload.
3. Less Efficient Running Economy
Running economy refers to how efficiently you can maintain a given pace. Self-propelled treadmills force a less efficient running pattern, meaning more energy is required for the same speed.
4. Constant Positional Awareness
You must maintain your position on the belt, which requires additional mental and physical energy.
Adjust Your Expectations
If you’re using a self-propelled treadmill, expect your paces to be slower than what you’d achieve on a regular treadmill or road. This isn’t a reflection of poor fitness – it’s simply the nature of the equipment.
Focus on RPE Over Pace
The best recommendation is to slow down your pace to match your desired RPE (rate of perceived exertion) or intensity zone. Since these treadmills are physiologically harder, you’ll need to run slower to achieve the same relative intensity.
Use Them Strategically
Self-propelled treadmills can be excellent tools for:
I personally love the assault treadmill in my gym for doing running intervals and conditioning workouts. It makes transitioning between different exercises really convenient, and I appreciate the additional challenge it provides.
Right now I’m doing 400-meter repeats as part of my program, and I know that even though I have general goal paces, they’re going to be slower on the assault treadmill because it’s simply harder. I’m not getting frustrated with my performance – I’m just aware of this difference and focus on consistency week to week on the same modality.
Understanding how different training modalities affect your performance is crucial for effective programming. If you’re looking for structured cardio and conditioning programs that account for these variables, The Lyss Method provides comprehensive hybrid training that strategically incorporates various cardio modalities.
For those wanting to understand training zones and intensities better, my free zones calculator can help you determine appropriate effort levels across different training modalities.
If you’re interested in learning more about cardio fundamentals and how to program different types of conditioning work, check out my Cardio Essentials guide for evidence-based approaches to cardiovascular training.
This is a big fancy way of saying that yes, self-motorized assault treadmills are going to be physiologically harder to perform on. It’s not just in your head – these things are actually about 30% more challenging across multiple metrics including VO2 demand, caloric expenditure, and time to completion.
If you have an assault treadmill available and you’re afraid to use it or you hate it, I encourage you to try it. It can be an amazing piece of cardio equipment and a great way to challenge yourself. Just don’t bring shame into the conversation when looking at your running paces or intensities – especially on an assault treadmill.
Remember: it’s harder, and that’s okay. Adjust your expectations, focus on effort over pace, and use these machines strategically as part of a well-rounded training program.
Keywords: assault treadmill, self-propelled treadmill, curved treadmill, treadmill comparison, cardio equipment, running training, HIIT workouts, exercise physiology, running economy, VO2 max, conditioning workouts, gym equipment
I’m Exercise Physiologist, sports nutritionist, weight lifter, and ultra runner. I am here to bring science to your training in a no-nonsense way. I have helped thousands of women crush big lifting goals, cross race finish lines, and even do both. I’m here to help you do the same!
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