The responses to my last two posts on how to run well on a treadmill have made it clear that runners of all kinds and levels agree on one thing: running on a treadmill is incredibly boring. Hence the temptation to make treadmill running your TV time. I totally understand that temptation, but I’m here to say you have to fight it. Let me tell you why.
A Sensory Mismatch
One of the many problems with treadmills is that the way your body’s moving tells your nervous system you’re going somewhere while all the rest of your senses tell you that you’re not.
The first few times you get on a treadmill this can feel very strange, and probably affects your movements in a myriad of ways, but as this study suggests, the brain adjusts to this mismatch once you’ve accumulated enough experience running on treadmills.
However watching something on a screen takes the visual/movement disconnect to a whole new level by asking you to do something with your vision that’s incompatible with how the rest of you is moving…even if all you’re watching is nature scenes or a simulation of running a race.
That’s partly because when a screen is really close, your vertical oscillation–the bouncing that’s a necessary part of running–makes what you’re watching seem to bounce. And your side-to-side weight shift makes it also seem to bounce side to side.
When you’re running outdoors, what you see is much farther away than a TV screen and on a much larger scale, so you don’t notice any bouncing. You just see a smooth movement of the world around you.
The only way to really notice your bounce is to wear a baseball cap when you run, and look at the world just below the brim. You’ll see the brim bounces up and down relative to the view in front of you.
However when the entire view in front of you is a smallish TV two feet from your nose, you see that bouncing and it interferes with your ability to follow what you’re watching. So you subconsciously reduce your head movement, dampening your bouncing and reducing the side-to-side movement. This goes double if you’re trying to read subtitles.
The effect of this on your movement is to significantly interfere with your mechanisms for harnessing ground reaction force and turning it into propulsion. You hit the treadmill harder with each foot, you work harder at a given speed, and your body becomes much tenser. Take that running form outdoors and you’ll be very uncomfortable and disappointed with your performance.
In short, watching TV on the treadmill requires you to run with form that’s completely the opposite of what I’ve seen in the world’s best distance runners and blogged about for many years. (My free one-week Mind Your Running Challenge is the best place to start learning world class running form. Try it here.)
The smaller the screen, the bigger the effect, so don’t even think of watching something on your phone!
Tough to Solve
So I’ve persuaded you to turn the TV off. Great! But unfortunately that leaves you with another problem: a blackened screen 2 feet from your nose.
I learned as a dancer that how far away you focus your eyes affects how you move. I’m not aware of any studies showing this effect in treadmill running but it is real. When your eyes tell you there’s a wall right in front of you, you alter your gait to move less dynamically forward. You hold your head differently. And before long you find yourself either studying your reflection in the screen or trying to find something else—anything else!—to look at.
There are companies that sell virtual reality programs for treadmill running, trying to create the experience of running a race or in a beautiful environment. I haven’t tried that on the treadmill but the stair climber at my gym has one, and while it reduces the unpleasantness of the normal gym view, it’s far from a virtual reality experience.
The physical fact is that even though you’re looking at an image of space, your eyes stay focused at a distance of about 2 feet in front of you. That doesn’t change, so your brain doesn’t get the signal of open space that would change your gait.
Nor does it change the information your vestibular system gets. As far as your inner ears know, you’re just bouncing up and down and—hopefully—slightly sideways with each step, and not moving forward.
So while a TV with a virtual race or trail app might also reduce the unpleasantness of treadmill running, it doesn’t make your gait more normal, especially if you try to actually watch it rather than just letting your eyes take it in in an unfocused way.
Another effect of looking at a screen in front of you is that you use central rather than peripheral vision. A tight rather than open focus. This increases stress and makes your run much less stress-reducing than a run outdoors would be. You can read more about that here.
So if you have any control of your treadmill situation, make sure you’re right in front of a window with a wide and beautiful vista. It’ll still stay put, but your eyes can change focus and roam, and your nervous system won’t be subtly preparing to run into a wall.
If your treadmill situation is like mine–a black TV screen right in front of your face–definitely keep it off, use it like a mirror to check your upper body movement but try not to lock onto it and obsess, and try to use your peripheral vision instead, taking in the room around you and not looking at anything in particular.
And, I freely admit it, listening to an audiobook can help draw your attention away from the visual to that auditory and imaginary. It’s better than nothing.