We know that the treadmill is a different experience than running outside. Some of us believe time on the treadmill is like the fate of Sisyphus. Others find it easier on the body than hitting the roads.
Whichever side you fall on, you may have heard to set the treadmill to a 1% incline to mimic outdoor running. This advice, given for decades, is said to replicate the energy cost of wind resistance during outdoor running.
But, not so fast, should you set your treadmill to 1% every time you run on it? Let’s delve into this below!
Origins of the 1% Rule
While there is research to support the claim “to mimic the energy cost of wind resistance during outdoor running, one should run at a 1% incline while on the treadmill”. That data supports that the energy costs are equivalent when running at 8 mph or faster (7:30 min/mile pace or faster).
How Has this Research Been Applied Historically?
Historically speaking, coaches, articles, athletes, influencers, etc., have used this information to suggest that ALL running (regardless of pace) should be done at a 1% incline on a treadmill.
Meaning, many people are acting on this information without any physiological reason to back it up. Which begs the question, if you’re running slower than an 8 mph on the treadmill, does it matter if you follow the 1% rule or not?
Considerations
Risk assessments are important whenever we are changing training stimuli. Doing all your running at a 1% incline on the treadmill can stress your calves/Achilles compared to the natural variation of inclines in outdoor runs. For many athletes, this presents an injury risk.
Remember, the treadmill is a tool. Like all tools, it has benefits and drawbacks. While a treadmill can’t fully mimic the “energy expenditure” of an outdoor run, it offers various ways to challenge our bodies and minds.