Why is it easier to run upstairs than down?

Physics and physiology aren’t my strong suits, so could someone please explain to me why it’s so much easier and faster to bound up the stairs than down them? Intuitively one would think that going down would be faster due to the gravity assist, but in my experience running or leaping down a flight of stairs safely requires a lot more time and care.

Gravity does assist, and that’s the problem - each step down causes an acceleration which you have to counteract or else momentum builds and …

When you’re walking or running, you’re essentially falling forwards and catching yourself with each step thereby propelling yourself forwards. Running up the stairs, you have a much shorter distance to fall and therefore it’s easier to catch yourself. Downstairs, the next step is much further away. Plus gravity doesn’t help much since you’re moving much faster forward and down than upstairs.

Running and walking involves lifting the leading foot - when the next step is above the level of the trailing foot, this just sort of works naturally.
When you are walking down steps, your leading foot has to be planted at a lower level than the trailing foot, which means the trailing leg has to flex, to lower the body down.

Notice that it’s not just stairs. I think this effect is even more noticeable on a ladder. I’ve long suspected that part of the reason is that when going up, you can see your destination (ie, the next place to put your foot) better, whereas when going down there’s more guesswork involved, so it is harder to keep your balance.

(I think there’s another area where we must account for the brainpower involved in keeping one’s balance: One traverses rough terrain more slowly than smooth. If I were comparing parkland to a paved surface you could blame it on traction and friction, but I’ve noticed this also when comparing a rough parkland (with many small hills and valleys) to a very flat lawn.)

That said, I hope we get a medical professional to chime in on this - a physical therapist, perhaps?

Speculation:
When you’re running upstairs, you begin decelerating as soon as you are airborne (after jumping upward off of a step). This gives you just a little more time to assess placement of your leading foot, taking some mental load off of your brain.

When you’re running downstairs, you begin accelerating as soon as you are airborne (after jumping downward off of a step). This gives you just a little less time to assess placement of your leading foot, meaning you have to devote more mental effort to the task.

There may also be a subconscious fear factor at work. If you stumble while running up stairs, gravity works to bring you to a halt quickly, and the worst that might happen is you skin your knees or sprain a toe. If you stumble while running downstairs, gravity is much more likely to make a violent mess of things. Might be that your brain is automatically trying to exercise more caution in the latter scenario.

There are some extreme ‘x-treme’ races through the woods where competitors run down boulder fields. They go insanely fast I’ve heard one say that he leaps first and figures out in the air where to land. I think it is the willingness to take risk that is part of that factor.

I think that illustrates the key difference; when you are going upwards, you are hauling yourself up; when you go down, you are repeatedly falling, then landing.

Not to mention of course that you are simply using different muscle groups for each different thing.

Because you are scared*.
If you go past that and teach you feet to run down stairs with 2 or 3 steps at the time, you will find you will be much, much faster going down.

It isn’t really hard to learn, you just have to stop being scared:)

*with good reason!

Mostly because the fastest way down stairs (or a hill) isn’t running.

It’s also similar to climbing a wall of rocks or climbing a tree: it is much (much!) easier climbing up than it is climbing down.

It’s all because of our eyes being near the top of our bodies: it is easier to see the ascending portions (rocks, tree, stairs, ladder as Keeve said) than the descending.

It’s all due to the position of our eyes.

Intersting.

Once in the air he has almost no control of where he lands. Ballistic trajectory and all that.

He does have some control over where and how he plants his feet when the ground arrives. That’s probably closer to what’s really going on even if that’s not how he perceives it.

Going up and down (stairs or hills) are completely different movements.

Going up, you plant your foot with bent leg, then use your big leg muscles to straighten your leg, propelling you the direction you want to go.

Going down, you plant with a straight leg, the use your muscles to slow down the bending of the leg, gravity is propelling you.

Big difference here is that when straightening the leg, there is a natural end point to the action, a fully straight leg, where you plant your next step. Going down, you start at the end point, and plant the next step at an indeterminate mid point of where your leg can bend. At that point your body is moving pretty quick and landing on a straight leg.

Q: What is black and white and black and white and black and white and black and blue?

A: A nun falling down the stairs

I have trekked up and down mountains and volcanoes, and virtually all the accidents I’ve witnessed have been from falling on the way down. I once took a nasty spill descending a volcano on the island of Guadeloupe, as a result of misjudging the distance while jumping off a boulder. In the ascent, I had simply climbed over it.

And if you have sore knees, it ALWAYS hurts more on the descent.

There may be some red in there too.

While running down stairs might be easier for short distances, try running up the stairs in the fire tower of a tall building.It gets old really fast. It may take more concentration to run down those stairs but I’ll take that any day over screaming thighs when going up…

Interesting. I always found running down the stairs way easier than up. I would generally just run down enough steps until I could jump to the landing, usually sliding my hand down the handrail to give me balance and afford me a higher jump point, turn the corner, and repeat. It’s fun. Meanwhile, running up the stairs just sucks.

If you were walking, stairs for going down would have about half the rate-of-fall of stairs for going up. For most modern stairs, this is handled by making the stairs as steep as possible while still safe – you’d really like your “up” stairs to be much steeper.

But that means that your “down” stairs are already as steep as the builders can safely make them, and means that if you go down any faster, you’re already going down faster than the stairs are designed for.

It applies to running on hills also. I used to run cross country and jog on rural roads. If the decline is too steep you have to retard each step and it is very jarring. But there is a wonderful sweet spot where the hill is just perfectly matched to your stride and you sail along like Superman. Doesn’t happen very often.