On March 23, 2013, at the pyramid of the Sun in México, a gust of wind blew my wide brimmed hat off just as I was stepping down onto the first step to descend to ground level. I grabbed at my hat and only the heel of my foot hit the first step, twisting my ankle and causing me to fall down a dozen or so rock steps (photo above).
While our shoulders normally have the largest range of movement of any joint, my shoulders both have torn rotator cuffs (the ligaments holding the arm in place at the shoulder). Any movement is painful and a sudden jolt on my arms would worsen the damage, so I consciously could not use my arms to try to stop myself from tumbling lenghthwise, from head to foot, down to the bottom of the stairs. Without my arms, wierd as it may seem, I couldn't check the forward/downward motion. Fortunately for me, I only acquired minor damage.
One of the injuries was a fractured rib (not broken). When a rib has even a small fracture, breathing and coughing are painful as is turning in bed at night.
Thanks to this injury, I developed some insight into a reality that is important to us in the martial arts.
You may note that there is a rather large boney protrusion on the inside of your elbow joint, roughly the size of the knuckle of your middle finger—the knuckle which karate exponents are advised to focus our punches on. It is a bit less than a square inch.
Because I couldn't extend my arms, that elbow protrusion was located along the side of my torso at my ribs. When I fell onto the rocky steps, the weight of my falling body was on the outer side of my elbow, sharply forcing the inner elbow protrusion into my rib and fracturing my 7th rib...the most commonly fractured rib.
SINCE I WEIGH AROUND 180 LBS., THAT IS THEN THE AMOUNT OF FORCE THAT FRACTURED MY RIB.. My bone density is normal. So, can a punch with the fist's middle knuckle really fracture a rib? YES--if it has around 180 pounds of force! What force does your punch have? CLICK here for related information
But the amount of damage your blow might inflict on a rib also varies due to factors such as the amount of muscle or fat covering it and the angle at which the blow lands; as well as the age and health of your opponent. Although it makes sense that a massive fighter can deliver more powerful blows than a lightweight, it's also about how much of your body's weight and muscle power you can “use." Some small guys hit with a lot of force because they know how to use their mass. That's why we practice getting our body's weight into the punch.
The punches of Martial Arts practicioners generally have less force than those of boxers. A study of 12 karate black belts showed the reverse punches delivered an average force of 325 pounds. Olympic boxers in weight classes ranging from flyweight to super heavyweight showed a range of 447 to 1,066 pounds of peak punching force.
Bone is extraordinarily strong — ounce for ounce, bone is stronger than steel, since a bar of steel of comparable size would weigh four or five times as much. When you perform CPR, you can give chest compressions and not break any ribs, but if you apply the same amount of force quickly instead of slowly, and you can end up causing rib fractures
When it comes to knocking someone out with a punch, it's less about the force of the blow than it is getting the head to whip around, to move in a rotational kind of way. The shear force from a strike that whips the head back or around stresses out neurons, and the brain shuts down as a protective response. That's why boxers and full contact competitors build up neck muscles — the thinking is that they can prevent that kind of motion. It's also about anticipating the blow. The blows that catch you off guard can be more devistating.
Studies have shown the amount of force per square inch necessary for breaking damage to other bones:
frontal bone ( forehead)- 1900 lbs
back of head (occiptal)- 2100 lbs
temporal - 1400 lbs
cheek bone-800 lbs
mandible - 800 lbs
cervical vertebra - 500 lbs
crown of head - 1350 lbs