Tackling treadmill myths and misconceptions
Updated: Oct 5
Is running on a treadmill the same as running outdoors? Do you run faster on a treadmill? What’s with the 1% incline rule? Does treadmill running mess with your mechanics? Does treadmill running create “lazy” runners & weak muscles? These are the treadmill myths & misconceptions that we will clarify in this blog.
Treadmills were originally built as torture devices, meant to break the mind, body, and spirit of English prisoners. Britain banned treadmills in 1989, seeing their punishment no longer useful. Fast forward 200 years and they are now a staple piece of equipment in gyms and home gyms alike.
Do you run faster on a treadmill?
Most people tend to find they run faster on a treadmill, and there are a couple of reasons why. Firstly energy cost is lower on the treadmill due to lower air resistance. Many scientific studies suggest using an incline of 1% to adjust for this, but more on this later. Secondly, calibration of treadmills is often an issue: the running speed displayed on a treadmill is not always accurate. Treadmills that have not been calibrated can OVERESTIMATE distance by as much as 2%.
On the flip side, some people can find running on a treadmill HARDER, and this is likely due to motivation: some runners find it exceptionally boring to run on a treadmill. After all, as mentioned earlier, the treadmill was once a torture device! Some also find running on a treadmill very unnatural and can be cautious about the risk of falling off or getting thrown off the back, so this can make for a harder running effort! A recent review by Miller et al found that the rate of perceived exertion was higher at faster treadmill speeds (they found it more difficult).
The 1% incline rule
As mentioned above, many recommend having a 1% incline on a treadmill to counter for the difference in air resistance. When you run, even on a still day, there will be wind resistance pushing you back. But unlike cyclists traveling at much faster speeds, for the runner, air resistance only comes into play at faster running speeds. The 1% rule often quoted is an AVERAGE value, and as you can see in the graph below, this will change with speed.
An incline of 1% might be applicable at speeds between 3:30-4:30min/km, but at 5:30min/km, the ideal incline decreases to 0.5%, and at progressively slower speeds, the incline drops close to 0%. One caveat here, however, is that air resistance varies depending on the runner’s body shape (taller & wider runners face higher air resistance).
A recent systematic review & meta-analysis by Miller et al examined a number of studies and found that running at submaximal speeds at 0% and 1% incline was NOT statistically different between treadmill & overground running. However, at maximal speeds, a 1% incline on a treadmill more closely resembled overground running.
Another important consideration is the impact of changing the incline on your running mechanics (how you run). Increasing the incline does change running biomechanics and increases the demand on the calf, Achilles, and feet. However, if the incline is kept under 2% this change is only minimal.
How about just increasing the speed on the treadmill?
Instead of increasing the incline, the other option on a treadmill is to slightly increase the speed. As mentioned previously, treadmill calibration issues often OVERESTIMATES speed, so bumping up the speed a small amount may actually correct for this. We recommend using a nifty conversion chart developed by Cody Beals (link here) which you can see in the image below. For example, if you were meant to be doing some harder interval running at around 4min/km, you could increase the speed slightly to just under 3:55. The advantage of increasing the speed is that it eliminates any potential issue with a change in biomechanics that an increased incline may bring.
Does treadmill running create weak muscles & ruin your mechanics?
Critics of treadmill running will often claim that running on a treadmill messes with your running technique and creates “lazy muscles”.
A recent systematic review by Van Hooren et al investigated if treadmill running changes running mechanics (technique) & muscle activation patterns. Whilst there were some subtle differences (read more on this below), overall the biomechanics and muscle activation patterns of treadmill running is largely comparable to overground running.
For the in-depth details on what Van Hooren et al found in their study, motorized treadmill running diﬀers from overground on a number of sagittal plane outcome measures:
Slight increase in knee flexion at footstrike & a decrease in knee flexion ROM during the stance phase
Less vertical displacement
Slight decrease in foot-ground angle at footstrike
Decrease in peak propulsive force and an increase in the ankle sagittal plane joint movement
Slight increase in ground contact time
Conﬂicting ﬁndings were reported for the amplitude of muscle activity, with some studies reporting lower muscle activity during treadmill running and other studies reporting no diﬀerences. Whilst there was a trend for lower muscle activity on the treadmill, this was not statistically significant, so we can’t say either way here if treadmill running creates lazy muscles.
What about treadmill use for injury?
Bone compression and strain, and plantar fascia strain has been found to be LOWER in treadmill running, and therefore may be more suitable for those suffering from stress fractures & plantar fasciopathy. However, peak forces and loading rates on the calf and Achilles tendon have been shown to be HIGHER during treadmill running, so those recovering from calf strains and Achilles tendinopathy might be best to stick to overground running.
At slower speeds (5min/km +), instead of increasing the incline, just bump the speed up a bit so the EFFORT is equal
1% incline is really only necessary for running at faster paces between 3:30-4:30min/km
There are no large differences in biomechanics and muscle activation between running on a treadmill and running overground, so don’t worry about treadmill running ruining your running technique or weakening muscles
Treadmill running may be more beneficial for those recovering from bone stress injuries and plantar fasciopathy, but overground may better suit those with calf & Achilles issues.
For any assistance with your running injuries or performance, please don't hesitate to contact us at www.healthhp.com.au
Jones AM, Doust JH. A 1% treadmill grade most accurately reflects the energetic cost of outdoor running. J Sports Sci. 1996;14(4):321-327. doi:10.1080/02640419608727717
Miller JR, Van Hooren B, Bishop C, Buckley JD, Willy RW, Fuller JT. A Systematic Review and Meta-Analysis of Crossover Studies Comparing Physiological, Perceptual and Performance Measures Between Treadmill and Overground Running. Sports Med. 2019;49(5):763-782. doi:10.1007/s40279-019-01087-9
Riley PO, Dicharry J, Franz J, Della Croce U, Wilder RP, Kerrigan DC. A kinematics and kinetic comparison of overground and treadmill running. Med Sci Sports Exerc. 2008;40(6):1093-1100. doi:10.1249/MSS.0b013e3181677530
Van Hooren B, Fuller JT, Buckley JD, et al. Is Motorized Treadmill Running Biomechanically Comparable to Overground Running? A Systematic Review and Meta-Analysis of Cross-Over Studies. Sports Med. 2020;50(4):785-813. doi:10.1007/s40279-019-01237-z