Maybe the weather’s crappy, or you just prefer the gentle give and programmable pace of treadmill running. Whatever your reasons, you may have heard hardcore runners say hoofing it outdoors and over-ground beats a treadmill every time. In some ways they may be right. But with a few tweaks, you can balance the benefits.
A NEED FOR SPEED
Maybe you’re the type who times every mile and knows exactly how to program a treadmill to match your outdoor pace. But if you’re more laissez faire about monitoring yourself, chances are good you’re running much slower on your treadmill than you would outdoors, suggests a 2012 study in the journal Gait Posture.
The study team asked people to run over ground, and then to step onto a treadmill and set it to the same speed. The catch: The runners couldn’t time themselves, so they were doing this by feel. Compared to their over-ground pace, the runners’ slowed their mile time by two minutes on the treadmill. This held even when the runners hopped off the treadmill and started running again over ground; their pace jumped back up, the study shows.
Running in place may mess with your visual input, the study authors say. (Your brain knows your body’s running, but your eyes are telling it you’re standing still.) That could explain your inability to match speeds on a treadmill and over-ground. But by measuring your speed or mile pace outdoors, you can set your treadmill accordingly.
RESISTANCE IS NOT FUTILE
In a famous treadmill study, UK researchers attempted to gauge the impact of air resistance on those running outdoors. Their goal: to find the appropriate treadmill incline—or “grade”—to replicate that resistance.
If your outdoor mile pace is 7:09 or faster, adjusting the incline on a treadmill to 1% will replicate the resistance you’d encounter running outdoors, the study concludes. But this part of the study is rarely reported: If your mile pace is slower than 7:09, you’re not running fast enough for air resistance to matter much. (Unless you’re fond of running in super-windy conditions, in which case that’s going to be tough to replicate indoors on a treadmill.)
VARIETY IS THE INJURY-PREVENTING SPICE OF RUNNING
Running researchers get excited about “kinematics.” Put simply, that term refers to the way your feet, legs and joints move and experience force as you run. It may surprise you that the kinematics of both treadmill and over-ground running are very similar, concludes a study in the Journal of Applied Biomechanics.
What’s not similar: When you’re running through a neighborhood or on a wooded trail—or pretty much anywhere outdoors apart from a perfectly flat track—your kinematics change as you run up hills, over puddles, and around cars and strollers. And those variations may protect your from injury, the research suggests.
In a nutshell, the research suggests the consistency of your running motion on a treadmill may increase your risk for common types of “overload” injuries to your muscles, tendons, bones or cartilage. While it may be tough to mimic on a treadmill the kinds cuts, sidesteps and other small adjustments you’d have to make running outdoors, varying your speed and incline throughout your run may help, the research indicates.