How To Fall

Let's talk about how to fall. I know that sounds ridiculous but let me explain. Anybody can fall, falling without getting hurt is another story. Knowing how to fall is just as important for a teenage football player as it is for a 80 year old with a cracked hip. Although being a bi-ped gives us many evolutionary advantages, its a horrible engineering design. Our bodies are inherently unstable and would fall over without hundreds of coordinated muscle contractions per second in our legs, its a wonder we can stand at all. A four legged design is infinitely superior to an engineer's eyes. We are the equivalent of a high performance fly-by-wire jet fighter, if the computer dies, we hit the dirt ... hard.

Even if you never do anything athletic or "dangerous" in your life, accidents happen. You will trip over a curb. You will step on your own shoelace. You will get up too fast and get dizzy. Knowing how to fall is not just for Hollywood stuntmen, gymnasts, and WWF wrestlers, its an essential skill for everyone. Human instinct when you fall is to put your arms out stiff like steel I-beams to keep from hitting your head. This is exactly why there are so many broken wrists from rollerblading and snowboarding, the "stick your hands out" method of falling.

Sky-divers are the world pros of falling safely. The newfangled high lift chutes allow cushy, easy landings but the old fashioned round chutes like those used in WWII required a lot more technique to safely land.   Before they let you do your first jump from a plane using these kinds of chutes, you spend several days jumping off progressively higher ladders and learning how to fall. One method of teaching the landing is the "banana method". Rather than landing like a pencil, you land like a banana. If a skydiver landed stiff and straight like a pencil, they would most likely break their legs, spine, or both. We will cover why in a minute. The banana technique on the other hand may not look pretty but it lets a skydiver land without a bruise, break, or scratch. They roll rather than jackhammer into the ground.

Lets look at the physics of falling. Force is what breaks bones, we want to minimize force.

Force = mass * (de)acceleration

To make the force less we can either make the mass less or the acceleration less. Well, if you are a skydiver losing weight so that you are fit and trim is a great way to lower the landing impact but that requires long term planning. Normally lowering the mass is not an option, which leaves lowering the acceleration. Acceleration is the rate at which the speed changes. We are going fast and we end up motionless.

acceleration = change in speed / time duration

So lets take our skydivers again, the pencil and the banana. Lets say they are falling at 3m/s with their chute open. The banana landing takes 0.1 seconds whereas the pencil landing takes 0.01 seconds, lets calculate the acceleration in both cases

  • pencil landing method acceleration = (3m/sec) / (0.01 sec) = 300m/s^2
  • banana landing method acceleration = (3m/sec) / (0.1 sec) = 30m/s^2

Assuming a 100kg man, lets calculate the force on each of our skydivers using F=m*a:

  • Force using pencil landing method: 100kg * 300m/s^2 = 30,000 kg-m/s^2 or 30,000 Neutons
  • Force using banana landing method: 100kg * 30m/s^2 = 3,000 kg-m/s^2 or 3,000 Neutons

What a difference in force!  A difference between shattering bones and walking away without a scratch.  The take home message here is to make your deceleration last as long as possible to minimize injury.  How to do that obviously depends on the situation.  If one of your buddies steps on your shoelaces while the other pushes you over you don't have a lot of options, but think, how can you minimize deceleration.  If you stiff-arm it then you are like the skydiver doing the pencil landing an you will most like bust something.  You cant roll because your feet are being held to the floor but you can pushup-land - hands out into pushup position, as soon at they touch floor start to bend at the elbow and take the force with your pecs.  Optimally you would finish stopping the fall just when your nose touches the floor.

I recently had a rather embarrassing bike fall.  For those of you who don't cycle, we often use "clipless pedals" which is a really stupid name because your feet are clipped to the pedals.  To disconnect the foot from the pedal requires a twisting motion and some pre-planning.  Beginner cyclists usually fall quite a few times learning how to deal with being connected to their bikes so intimately.  Where this happens is at the stop, the beginner forgets they are clipped in and when they go to put their foot down at the stop, they find their foot stuck and over they go.   Well anyway, I have been using clipless pedals for 25 years and haven't fallen at a stop sign in 20 years so when it happens, its really embarrassing.  I wont go into why this happened but a surprise stop is usually the cause.   Anyway, knowing how to fall saved me.  Rather than putting my hands out in panic to stop the fall I relaxed and rolled by pushing my hip and knee into the fall so I made a nice banana shape which would roll rather than ka-thunk into the pavement.

You know the expression, "Its as easy as falling off a horse". Well, falling off a horse is easy but learning to be thrown from the horse, and roll without getting hurt takes a lot more practice. Its instinct to put your hands out and fall like a tree and takes a lot of practice to overcome it. When I took Tae Kwon Do, the first thing we learned was how to be thrown without getting hurt and that skill has served me well ever since. I'm a big guy and I fall really hard so back when I did a lot of rollerblading and snowboarding, knowing how to tuck and roll prevented many a broken bone.  Learning how to tuck and roll isn't something that you can really teach yourself at home because its just not safe.  Its also something that you cant learn in a day. You can get enough proficiency in a few months to save your bacon but to truly make it an automatic reflex takes years.  Please consider taking a martial arts class, or if you are older, take a tumbling class for adults to learn how to fall. They have thick mats where you can safely learn how to fall and most importantly they can give the proper instruction to keep you from landing on your head.

How To Fall

Learn The Banana!