How Treadmills Differ From Running Outside: 5 Must-Do Tips

Practical Guidelines For Treadmill Running

• Undulating the treadmill speed will mimic outside running better than constant speeds.

• Undulating treadmill incline between 1% and 2% is a good idea.

• Heart rate and perceived effort may be higher on a treadmill at faster paces and lower at slower paces.

• Endurance performance may be lower on a treadmill, perhaps due to boredom.

• Due to treadmill (and indoor GPS watch) calibration inaccuracies running by effort is the best method for treadmill running

Want to know why you should do these? Read on...

Love them or hate them, treadmills can be an incredible asset to any runner's training program. One of the biggest questions I get every winter as a running coach is, “How does running on a treadmill compare to running outside?”

Well, I’ve got good news. Scientific studies have shown that running on a treadmill with a few minor adjustments is very similar metabolically and mechanically to running outside.

Let’s take a closer look at what metabolically and mechanically actually mean.

Does Running Form Change on A Treadmill

Mechanically means how your body moves when you run. It is also called running economy or running form. In short, there are minor but insignificant differences in running form between running on a treadmill and outside.

One of the larger and more throughout studies (systematic review and meta-analysis of cross-over studies reviewed 33 studies totaling 494 participants) from 2020 found that “muscle activity and muscle-tendon outcome measures are largely comparable between motorized treadmill and overground running.”

Another smaller study dug a little deeper into the differences in running form to find that running on a treadmill and overground produced similar levels of muscular activity under all circumstances.

However, it was determined that the muscle activity was most comparable for thigh muscles when the treadmill grade was 1% and for ankle stabilizing muscles when the grade was 2%.

In other words, athletes who use treadmills for their training can have confidence that the muscles they use for running are utilized similarly to when running outside on regular terrain.

Interestingly, the study also found that your stride was more inconsistent during running outside than running on a treadmill. This is because the treadmill restricts your stride pattern due to a lack of surface angle and speed viability.

Incorporating some diversity into your stride benefits your health and athletic performance. If you plan on using the treadmill extensively for training, vary your running speed periodically throughout your session.

Do You Get The Same Cardio Workout On a Treadmill as Running Outside?

One small study examined seven male runners to compare VO2 Max (a measure of your maximum oxygen uptake) differences between running on a treadmill and running outside. They found no statistically significant.

Another much larger study found that running incline and speed greatly influenced differences in heart rate, blood lactate levels, and perceived effort running on a treadmill versus running outside.

They found similar oxygen usage (which supports the previous study’s findings) but lower blood lactate occurred during submaximal treadmill running at 0% and at 1% grade than during overground running.

Heart rate and perceived effort during treadmill running were higher at faster speeds and lower at slower speeds than during outside running. Similarly, they found oxygen usage and blood lactate levels tended to be lower. But at near-maximal (aka sprints) speeds heart rate and perceived effort were similar. They also found endurance performance was poorer on the treadmill, this is perhaps due to the monotony of treadmill running.

One Last Important Thing To Consider: Treadmill Accuracy

One of the most overlooked factors when discussing the difference between treadmill running and outside running is most treadmills are not calibrated accurately. This means the speed and distance you’re actually running on a treadmill can vary greatly from what the treadmill and GPS watches say.

Because of this and the differences found in the above study running by effort is the best method to mimic outside running on a treadmill. If a particular pace feels like the pace you’d be running outside, run with it. At the of the day, it’s not the seconds that matter. It's the effort.