In 2000, Alaska resident Christine Clark won the U.S. Women’s Olympic Marathon Trials after training on her treadmill all winter.
In 2020 CJ Albertson ran a 2:09:58 marathon on his treadmill, and soon added top real-marathon performances to his resume. Albertson eventually achieved a marathon PR of 2:08:17.
But now, here comes Vinny Mauri, who runs treadmill workouts like a visitor from another planet. Maybe that’s why he favors Planet Fitness for his astounding efforts.
Last April, in his first marathon, the unknown Mauri ran an eye-popping 2:05:54 entirely on his own in Toledo, Ohio. He is a 25-year-old who attended Arizona State and Notre Dame.
When LetsRun.com recently dug into Mauri’s treadmill training, a few efforts stood out. He does most of his training on treadmills and has averaged over 120 miles/week for the last 10 weeks. On one September day, he did two sessions totaling 36 miles at an average pace of 4:56 per mile. The week before, he ran 30 miles at a 5:01 per mile pace.
Mauri will run his second marathon Sunday morning in Chicago. He says he’s in much better shape than last April and plans to match strides with Clayton Young and Charles Hicks, who aim to break Conner Mantz’s American marathon record of 2:04:43. CJ Albertson is also entered.
Mauri might have a great day in Chicago, or he might not. Either way, the bigger question for all runners is this: Is treadmill training a good way to prepare for your next big race?
From Prison Punishment to Home Gym Staple: A Brief History of the Treadmill
While treadmill-like devices were first used as crude human-powered machines and later to torture inmates in British prisons, they entered the world of scientific research at the Harvard Fatigue Laboratory in the 1920s. Researchers tested runners like Clarence DeMar (the 7-time Boston Marathon winner) and miler Glenn Cunningham in some of the earliest exercise physiology experiments.
But there was no wider market for treadmills, because there were few recreational runners. They didn’t enter the scene until the first Running Boom of the late 1970s.
At that time, most treadmills were bulky, jerky, noisy, and couldn’t reach high speeds or handle inclines/declines. Worse, serious runners ridiculed them and the whole idea of running indoors. If you did so, you were considered a “jogger,” not a real athlete.
Today’s treadmills offer a smooth experience, a vast array of digital options, and, on specialized anti-gravity models, the ability to support part of your body weight to reduce impact and injury risk. They are considered the world’s most popular home fitness machine. Most importantly, the convenience of home use increases your chances of sticking with your training program through bad weather like cold, heat, darkness, and precipitation.
But that doesn’t answer the key question: Are treadmills actually an effective way to prepare for your next big race or marathon?
Does the Treadmill Build the Same Fitness as the Road?
Of course, exercise physiologists and biomechanists have been studying this for some time. It’s not easy, for all the usual reasons. Treadmills are different, runners are different, the shoes that runners wear on the treadmill are different, and so on.
But scientists keep plugging away because they are disciplined and determined, just like marathon runners. The field is dominated by two big questions. First, when you run on a treadmill, do you get the same physiological experience, and therefore the same training benefits, as when you run on the road?
After all, if treadmills are dramatically different from roads (perhaps “easier”), then you wouldn’t gain fitness as readily on the treadmill.
Second, does treadmill running change your biomechanics? That is, your running form? If it does, it might increase or decrease your injury risk. This is crucial information for all runners.
Dutch researcher and 1:02 half marathon runner Bas van Hooren, PhD, is one of the world’s experts on these questions. He has been a co-author on two recent, highly influential papers in the field.
The first is titled “A Systematic Review and Meta-Analysis of Crossover Studies Comparing Physiological, Perceptual and Performance Measures Between Treadmill and Overground Running.”1Miller, J. R., Van Hooren, B., Bishop, C., Buckley, J. D., Willy, R. W., & Fuller, J. T. (2019). A Systematic Review and Meta-Analysis of Crossover Studies Comparing Physiological, Perceptual and Performance Measures Between Treadmill and Overground Running. Sports Medicine, 49(5), 763–782. https://doi.org/10.1007/s40279-019-01087-9 The second is titled “Is Motorized Treadmill Running Biomechanically Comparable to Overground Running? A Systematic Review and Meta-Analysis of Cross-Over Studies.”2Van Hooren, B., Fuller, J. T., Buckley, J. D., Miller, J. R., Sewell, K., Rao, G., Barton, C., Bishop, C., & Willy, R. W. (2019). Is Motorized Treadmill Running Biomechanically Comparable to Overground Running? A Systematic Review and Meta-Analysis of Cross-Over Studies. Sports Medicine, 50. https://doi.org/10.1007/s40279-019-01237-z
Cross-over studies test subjects under both conditions: running on a treadmill and running “overground,” as scientists call it. As such, the results from cross-over studies are considered strong evidence.
A Treadmill Researcher Answers Your Biggest Questions
Here, Bas van Hooren answers the most important questions about treadmill running for serious training benefits.
MH: Treadmill training is very popular. What’s good about it?
Bas van Hooren: One of the biggest advantages is the ability to precisely control running speed and incline, making it easier to perform structured workouts and monitor training progress. Treadmills also allow runners to train consistently regardless of weather conditions, traffic, or daylight, which can be particularly valuable during winter or in busy urban environments.
From a biomechanical perspective, treadmill running is generally highly similar to overground running if runners are accustomed to treadmill running, and if the treadmill stiffness is similar to the outdoor surface stiffness (see later question/answer). This means that most of the training adaptations should transfer well. Treadmills can also be useful for rehabilitation, as they allow precise manipulation of running speed and incline to influence loading of specific tissues.
Are there negatives?
Treadmill running lacks some of the variability encountered outdoors, including changes in terrain, turns, natural fluctuations in speed, and step-to-step variability. This leads to more monotonic loading of the same structures, which may increase overuse injury risk. Another limitation is that treadmill speed and incline are not always accurately calibrated, meaning that the displayed speed may differ from the actual running speed. Furthermore, some runners find treadmill running boring, and ventilation and cooling can be inadequate indoors, potentially increasing thermal strain and perceived exertion.
Many runners have heard they should run on a treadmill set to a 1% incline to offset the lack of air resistance. Is this true?
The 1% recommendation originates from a 1996 study indicating that it can better approximate the energetic cost of outdoor running at certain speeds compared to 0% incline. However, in a large meta-analysis, we showed that 0% inclination yields the same energetic cost as outdoor running. This suggests that a 1% inclination is not universally required, at least not for speeds up to approximately 6:00 minutes per mile. At higher speeds, you may have to use an incline to compensate for the larger effect of air resistance at higher speeds. This air resistance doesn’t exist on a treadmill, so an incline can simulate it.
Interesting note: In terms of energy cost, we have found that, theoretically, the best overall incline might be .5%.
Are treadmills “softer” and less injury-producing than the roads? When training for an upcoming race, is it important to do some workouts on your race-day surface?
We have done extensive research comparing the stiffness of treadmills to other surfaces, showing that almost all treadmills have more compliant [softer] running surfaces than asphalt. This can slightly change the way we run, and thereby alter loading forces. For example, running on compliant treadmills has been shown to reduce tibial and plantar fascia strains, but increase Achilles tendon loading.
That being said, there is insufficient evidence to conclude that treadmill running results in fewer, or more, injuries than road running. For runners preparing for road races, I would recommend including at least some outdoor tempo runs and longer runs. This helps them become accustomed to outdoor pacing, environmental conditions, terrain variations, and the specific demands of racing.
Are boredom and lack of actual movement through an environment a factor with treadmill running? Are there ways to overcome these?
Certainly, boredom is an issue for some runners, although this depends strongly on individual preferences. Running outdoors provides changing scenery, natural variations in terrain, and greater sensory stimulation, which can make running more enjoyable.
On the other hand, some runners appreciate the predictability of treadmill running and the opportunity to watch television, listen to podcasts, or follow virtual running routes. Modern treadmills with interactive displays and virtual environments can also make indoor running more engaging compared to the older days.
Another strategy is to introduce variation through structured intervals or changes in incline rather than running at a constant speed throughout the session. Ultimately, the best environment is one that helps runners enjoy their training and maintain consistency.
How would you describe the treadmill vs. overground differences generally? Small-Moderate-Significant? Is there any reason to avoid treadmill training if it makes your training regimen simpler and more enjoyable?
I would characterize the biomechanical differences as generally small to negligible. In our review, we found that most biomechanical variables were highly comparable between treadmill and overground running. There were some differences, particularly in foot placement at initial contact, but overall the similarities were much greater than the differences. For example, contact time was significantly longer on a treadmill, but the difference was very small: only 5 milliseconds.
I see no compelling reason to avoid treadmill training if it makes training more convenient or enjoyable. Consistency is one of the most important factors in successful endurance training, and anything that helps runners train consistently can be beneficial.
For runners training for a future race, I would recommend combining treadmill running with some outdoor sessions to ensure familiarity with race-specific conditions. But for most runners, treadmill running can be an excellent alternative to outdoor running.
References
RunClub — Free
Join 300,000+ runners in RunClub
Free training plans for every distance, a daily running game, exclusive coaching content, and a real community of runners. Create your free account in 20 seconds — no card.
Already a member? Log in →
Start the conversation