Treadmill vs outdoor running: what the research reviews show
Two systematic reviews of crossover studies compared treadmill and overground running. Biomechanics were largely comparable, with differences in how the foot lands. Heart rate and effort were higher on the treadmill at faster submaximal speeds and lower at slower ones. A 1% incline is a common setting, but it is a starting point.
What was reviewed
This guide uses three sources: a 2020 systematic review of biomechanics, a systematic review of physiological, perceptual and performance measures, and the 1996 laboratory study behind the 1% incline. Each answers a different question, so the table keeps them apart.
| Source | Question | Main finding |
|---|---|---|
| Van Hooren and colleagues, 2020 | Is treadmill running biomechanically comparable to overground running? | Largely comparable. Take care with footstrike kinematics. |
| Systematic review of physiological and perceptual measures | Do heart rate, effort and performance differ? | Some do, depending on speed. |
| Jones and Doust, 1996 | What incline matches the energy cost of outdoor running? | 1% in the speeds tested. |
Biomechanics
A 2020 review in Sports Medicine pooled crossover studies of non-inclined, motorized treadmill running against overground running in healthy adults aged 18 to 65. Most outcomes did not differ. The authors concluded that spatiotemporal, kinematic, kinetic, muscle activity and muscle-tendon outcomes are largely comparable, and advised care when applying treadmill findings to overground running because of sagittal plane kinematic differences at footstrike.[1]
Heart rate, effort and performance
A second systematic review compared physiological, perceptual and performance measures. Twelve of the included studies used a 1% grade for the treadmill condition. Heart rate and perceived effort during motorized treadmill running were higher at faster submaximal speeds and lower at slower submaximal speeds than during overground running. Maximal treadmill running produced similar oxygen uptake and heart rate to overground running. The authors concluded that some variables differ and that the differences may depend on running speed.[2]
The 1% incline
The 1% setting traces to a 1996 study that matched the energy cost of treadmill running to road running at speeds of 9:11 to 5:22 per mile over about five minutes.[3] Our treadmill incline guide goes through that study speed by speed.
How to set your treadmill pace
The display shows belt speed, and the pace does not change with incline. Convert the speed with the mph to min/mile converter or the speed to pace calculator, then compare it with your goal from the pace chart. Because heart rate and effort can differ from outdoors depending on speed, use effort as a check. The reviews do not say how much outdoor running you need for an outdoor race, so treat that as a judgment call.
Frequently asked questions
Is treadmill running the same as outdoor running?
In biomechanics, a 2020 review found most outcomes largely comparable. Heart rate and effort differed by speed in a second review, so the two are similar but not identical.
Does a treadmill make running easier?
It depends on speed. Heart rate and perceived effort were higher at faster submaximal speeds and lower at slower ones in a systematic review. The study of energy cost found a flat belt cheaper than the road at faster speeds, which a 1% incline offset.
What incline should I use?
A 1% incline matched the energy cost of road running at speeds from 9:11 to 5:22 per mile in a 1996 study. It is a sensible starting point, not a rule.
Sources
- Van Hooren, B., Fuller, J.T., Buckley, J.D., Miller, J.R., Sewell, K., Rao, G., Barton, C., Bishop, C. and Willy, R.W. (2020). Is motorized treadmill running biomechanically comparable to overground running? A systematic review and meta-analysis of cross-over studies. Sports Medicine, 50(4), 785–813.
- A systematic review and meta-analysis of crossover studies comparing physiological, perceptual and performance measures between treadmill and overground running. Sports Medicine. Authors include Bas Van Hooren.
- Jones, A.M. and Doust, J.H. (1996). A 1% treadmill grade most accurately reflects the energetic cost of outdoor running. Journal of Sports Sciences, 14(4), 321–327.
Related tools and guides
About the author
Shaheer Bin Ramzan is a software engineer and SEO specialist with five years of professional experience. He builds and checks the calculators and writes the guides on MilePaceLab. He is not a running coach or doctor. See the author page, the methodology and the disclaimer. Report errors through the contact page.