Introduction

The best heavyweight boxers were Joe Louis, Muhammad Ali, Evander Holyfield, Mike Tyson and then the list goes on. Strangely enough, they aren't huge men. In their primes, they weighed 100kg or less. With this article, I'll try to explain why bigger is not always better.　

Three dimensional world
First, one must understand that we live in a 3-D world. It may sound stupid but I'd say that 90% of the world thinks in 2-D but calls it 3-D.

When I was in my teens I enjoyed fake-wrestling. Sad I know. Anyway, I wanted to know how much I would weigh if I were the same height as Hulk Hogan. Hogan was 6'8" and I was 5'6" and weighed about 130 lbs. Using junior high school math, I thought this would be easy to work out. All I had to do was change the inches to a decimal and cross multiply.

6'8" = 6.66
5'6" = 5.5

6.66/x = 5.5/130
(6.66)(130) = 5.5x
865.8 = 5.5x
865.8/5.5 = x
157.4 = x

So, using cross multiplication I would weigh a whopping 157.4 lbs if I were 6'8". Somehow I knew this was impossible. I wasn't a chunky guy but I was expecting something like 230lbs. I was at a loss and too shy to ask my math teacher for help. I knew she would ask "why" and I didn't want to tell anyone that I watched WWF. That was beyond embarrassing. I tried to graph the figures. I put height on the y- axis and weight on the x- axis and the numbers always came out way too small.

Then it hit me, only two axes. People are three dimensional [height x width x depth]. These three dimensions together give us weight. I needed a new formula.

First I tried cubing 5', 6' and 7' to see what numbers would come up.
5 x 5 x 5 = 125
6 x 6 x 6 = 216
7 x 7 x 7 = 343
So, a five footer who weighed 125lbs would weigh 216lbs if he were magnified to a height of 6 feet and 343lbs at 7 feet. It looked good to me. A little simple but a fair rule of thumb.

Now what about me?
5.5 x 5.5 x 5.5 = 166.4

Stuck again. I didn't weigh 166.4lbs. I weighed 130lbs. Well, it didn't take me long to notice that 130 was simply 78% of 166.4.
130/166.4 = .781

Therefore,
(.781)(6.66 x 6.66 x 6.66) = my height at 6'8"

The answer turned out to be pretty funny, 230.7 lbs. I have since given up math and learned to trust my hunches. 　

A 9' Goddess! Wow!
Let's try an example of a 5' 100lb woman who is magically zapped into a 9' titaness with the same figure.

First, the wrong way:

5/100 = 9/x.

x= 180lbs.

A 9' 180lb woman? No way.

Next, the right way.

5x5x5 = 125

100/125 = .800

(.800)(9x9x9) = 583.2

So she would be 9' tall and weigh 583.2lbs. Cool. 　

Robert Wadlow was weak
My friends thought this was pretty fun. I could tell them how much they would weigh if the were 7' tall. Later, being kids, they wanted to know how much they would weigh if they were the same height as King Kong or Godzilla.

Then one little bastard ruined the fun by asking why the giants in the Guiness book of world records looked so unhealthy. Why were they falling apart? Why did they have such trouble walking? Why? Why? 

Robert Wadlow, at 8'11" and 490lbs, looked like crap. The bone and cartilage throughout his body couldn't match the weight.

Once you understand that the weight of a person is related to all 3 dimensions, next you need to observe how some other important factors are related to only 2 dimensions.  

Our giantess above probably wouldn't be able to walk very far either, if at all. Her weight went from 100lbs to 583lbs, a product of increasing her height, width and depth but her knee strength only increased in width and depth. So her weight multiplied 5.8x but her knee strength didn't. Which means she is holding a few hundred pounds more than her knee is designed to hold. This effect would take place all through her body. Her ankles and hips would have more weight grinding on the cartilage. Tendons would be strained. Life would feel heavy.  

Another example is the arteries near the heart and the heart muscle itself. The arteries would increase their height and width, only two dimensions. This means they could likewise supply enough oxygen for a person several hundred pounds lighter than a 583lb giant. As for the cardiac muscle, it would get thicker but thickness is only one dimension whereas the workload [the body] increased three dimensionally.

How about the lungs? Would the diaphragm be able to perform its job and support its own weight? Not likely.　

Skyscrapers
If two guys weigh the same but have different heights, would the work load be different?  

Let's say you are an engineer and your boss tells you that the 200 meter building you have been designing will now be 210 meters. Sounds easy, doesn't it? Just add ten meters to the top. Wrong. The water pumps in the basement must lift a 200 meter volume of water another 10 meters.

For the sake of an illustration, let's say the pipe has a radius of 15cm. That means a full pipe would have 1413kgs of water to lift 10 meters. Translation: you need a bigger pump to fight the pull of gravity. When you take a garden hose up to the roof, you notice that water pressure weakens considerably.

My reasoning is that the distance the heart has to pump the blood would be a factor. Even more so, the heart fighting the pull of the Earth would be harder on the taller athlete. There is little question in my mind that a tall athlete would demand more of his heart than a shorter athlete. The only question is how much more.　

Heat

Normal human body temperature is 37C. At 42C there will be a central nervous system breakdown and at 44C you will see dead relatives beckon. Don't worry. Your body will automatically kick in the cooling systems once you stray from the 37C. In fact, when the skin reaches 30C, perspiration begins.

Mammals [and some other animals like the tuna] generate heat when they move. The bigger the mammal, the more heat. We lose heat in a number of ways.  

The skin is extremely important in this function. However, larger people actually have less skin area per weight which means that they would have a harder time cooling off. 

Now for more numbers. I am going to calculate volume of different sized cubes, their surfaces areas. Then I'll show the ratio between surface area and volume. What you'll see is that the ratio decreases as the object gets larger. For the purposes of this illustration, let the volume of the cube represent the weight of the fighter and the surface area represent his skin. 

Volume = Height x Width x Depth

1x1x1 = 1
2x2x2 = 8
3x3x3 = 27
4x4x4 = 64
5x5x5 = 125
6x6x6 = 216
7x7x7 = 343
8x8x8 = 512
9x9x9 = 729
10x10x10 = 1000

Surface area

I don't know the surface area of a human being. For the sake of simplicity, I will illustrate that two objects with the same shape but different volumes will have different surface area to weight ratios. For this illustration again, I am using the simple cube, a six sided figure. The surface area of a cube is easy to calculate. Find the area of one side and multiply by 6 [left column].

The figures on the right show surface area to volume ratio. Notice how this number decreases as the object gets larger. We can therefore reach the logical conclusion that a supersize athlete would not only generate more heat but would have a less effective cooling system. 　

Athleticism

One last thing to consider is athleticism. Some people may just be bigger and healthier too. Sem Schilt is a very healthy giant. Many basketball players take their huge frames on the court for the greater part of the game. Some smaller fighters like Musashi have terrible cardio. One possible reason is that Musashi has a heart designed for a light heavy or cruiserweight but has bulked up for the k-1 at the expense of his stamina whereas Sem Schilt has a heart designed for a 120kg man.

Basketball players are interesting. We think of them as being fit but if the court were increased in area, you'd see the average height of the players drop accordingly. In fact, if the court were the size of a soccer field, that would be the end of the goliath game. On the other hand, there are some things I like about basketball players. They have to stay lean or they will quickly be replaced by young hungry rookies. Because of this they are giants in ever-peak condition.　

So in the fight game, how big is too big?

It depends. The more there is a demand for cardio the lighter the athlete has to be. In sumo, Konishiki weighed 275kg (605lbs) and reached the rank of Ozeki, second only to Yokuzuna. Wrestlers use their weight a lot also so 300+lb champs are not uncommon. In the K-1, Mark Hunt is the heaviest champ at 124kg (273lbs) before him the heaviest was Peter Aerts. In boxing there are more rounds so Lennox Lewis tries to weigh in the range of 245lbs and also takes great care not to over exert himself. Ali fought 15 rounds at 214lbs and Joe Louis was the last to be scheduled to fight 20 rounds [vs. Bob Pastor] where he weighed in under 200lbs. When we look at marathon runners who have the greatest demand on their cardio, the weight limit drops even further.　

ü       Weigh is a related to 3 dimensions while support is related to two dimensions.

ü       Large bodies create more heat and have to work harder to cool off.