[header] How to switch from treadmill running to outdoor running [title] Increase your treadmill's incline. [step] Your treadmill is completely flat, while most outdoor running surfaces are not. To help prepare your body for the difference, you can practice by running on an incline on your treadmill. 
[substeps] An incline of 1-2% closely simulates running outdoors. Program your treadmill so that it adjusts incline throughout your run, if the treadmill you use has this feature available.