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Indestructible Babies – Why Kids Aren't Easily Injured

Nice Aikido FallBaby Survives Fall from 7th-floor Paris Flat

Baby Survives Crash that Killed 3

Baby Falls Out of Bus Window, Survives

Those are real news articles about accidents involving babies. Miraculous survival stories that would have killed grown people, yet the delicate baby survives with barely a scratch. Who ever said babies and toddlers are fragile? They’re not. They’re made from the same meat and blood and bones that adults are, but they have some huge advantages that make them almost indestructible!

Physics Lesson

Force is what causes damage. The physical definition of FORCE= MASS X ACCELERATION. When a falling body hits the hard ground and stops abruptly, that is a huge acceleration (or de-acceleration in this case, but the force is the same). If the body is also heavy, the force is very large. If the body lands on a small weak piece, like the wrist, then that force punishes the wrist. If the force of the fall is larger than the breaking force, the wrist snaps.

Physics of a falling child.

A baby’s small size means a low MASS in the formula, which reduces the force.

A baby’s “crumple zone”, weak arms or a padded diaper, means that the landing is not abrupt.  This means low ACCELERATION, which reduces the force.

A baby’s ability to give up and land on his butt means that the force is spread over a large structure that is strong.

Example: If a toddlers mass is only 10% of an adult's, and the impact is twice as slow, that means the force acting on the baby is only 5% as big as the adult.  If the baby falls on a diaper-padded-bottom, the surface area might be 5 times as large as an adults wrist, meaning that the force is spread and the baby really only feels 1%.  Said another way, a falling adult might hit a structure with 100 times as much force as a baby:  An adult's wrist gets shattered, while the baby feels nothing.

I’m a third degree black belt in Aikido, a martial art in which you spend about half your practice time getting thrown down. I know what it takes to survive falls, and babies have it all!

Small Size

Babies and toddlers have a very small mass: 15, 20, 25 lbs. Very small adults have a mass of 90 lbs, or about four to six times as much. Most men are ten times as heavy or more! That means that the force of an adult impacting after a fall is four to ten times greater in an adult. The bigger they are, the harder they fall indeed!

One other problem with an adult is that the internal organs have a large mass.  This is very bad in a high speed accident because the organs are supposed to stay more-or-less in place but big, heavy organs are harder to hold tight.  Take the heart:  In a car accident the body gets jostled and, inside the chest, the heart gets thrown around.  Since the heart weighs a lot more there is a larger force and a larger danger of it ripping loose from the giant blood vessels it's attached to. Same with the brain. Concussions and brain damage happen when the brain is smashed around the cranium from an impact.  Baby organs are so much smaller and less massive that, internally, they can “stay together” even with a violent impact.

Weak Muscles – Crumple Zones

Toddlers are very weak, which is a good thing. Being trained in Aikido, I know that the secret to a feather-light fall is being soft – Aikido people let the body fold and bend in natural ways, absorbing the force in flexible pieces like a slinky (check this youtube video for an example). Untrained people become rigid, trying to protect the body with tension, but instead making it solid so that the full mass is felt at the point of impact.  Unfortunately the structure, like a wrist or a knee or a back or a neck, is not strong enough to stop a full impact all at once. Tendons rip, muscles strain, bones break.  Watch someone slip on the ice.  The instinct is to put out hands, and when these hit the ground first trying to hold up the body then bang!  Broken wrist.

Automobile crumple zones are engineering to be crushed in an accident to reduce the impact to the passengers. Cars could be made very stiff, but then in an accident the force is transmitted instead of dampened. Toddlers may also try to make themselves stiff when they fall, but they are so weak that whatever limbs they put out just end up folding to soften the fall rather than have a bone or joint explode.

Toddlers Give Up Fast

If you have a toddler at home then you know what I mean. Most of the time, as soon as they sense the slightest balance problem, they just sit down. An adult will often try to save themselves with a little dance. They go right to the edge of their balance, using up all their balance in a sense, before finally dropping hard. That means the fall, when it happens, is totally uncontrolled. Without balance in reserve, they just land how they land, on a hip, their back, their head, whatever. The toddler gives up early and just sits down in a much more cowardly but controlled and safe way.

A Baby is Structurally As Strong as an Adult

Nobody would say that a baby is physically as strong. The muscle strength is weak, as we’ve discussed. But the meat and the bones on a toddler are more-or-less the same meat and bones of an adult, just less of it. Babies are not made of tissue paper. It takes about the same kind of damage to cause a bruise or to cut the skin. Bones are lighter and thinner, but proportionally they are of similar strength. In fact, developing bones are less stiff, so they can absorb more before breaking. The baby has all the advantages!

There you have some of the reasons that babies survive certain kinds of horrific accidents much more easily than adults. Many parents have an instinct to over-protect. Falls and bumps around the house are not a problem at all for babies, even if they cry a little.  Toddlers can fall and bump into things twenty times a day, it's part of growing up and it will let the child develop body awareness and a certain toughness.  Don't leave open pits around or balance your child on the back of a chair, but you probably don't particularly need to pad the floors or carry them up and down the stairs of the playground slide.

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julie's picture

Love your website.  Thanks for visiting mine.  With all the reading I'm doing I really believe we are both right and left brained.  Some of us may tend towards art and such ..... other towards math.  Some of us (like me) are both.  My oldest loves music but hates art.  He's good, not great at Math but doesn't like to read.  His long term memory is amazing while short term memory is not.  He loves facts.....hates fiction.  Now I'm thinking about learning styles.......that coupled with the information I'm reading about right and left brain makes a lot of sense to me.