Exactly 100 years ago, in 1920, the fastest sprinting record in 100 meters was 10.6 seconds. A lot of people thought that it’s the limit and this record will never be broken and it’s beyond human capabilities. Slowly but surely, it kept breaking. In 1968, multiple sprinters broke 10-second barriers printing 100 meters in 9.9 seconds. Then again, people thought that said it’s the limit. But now, in 2021, we have Usain Bolt who holds the record of 9.58 seconds and known as the fastest man on the planet. Even now, you can find some people saying that no one can break the current record. Is this really true? How fast can a human run? Let’s take a look at the limitations behind running faster.
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Why Humans cannot Run Faster than Animals?
You know that we humans are not the fastest animals and this is immediately obvious from our Anatomy.
For example, we have heavy calve muscles who weigh down on our legs. The calf muscle must swing back and forth at every leg stroke and require a lot of force to allow any increase of the frequency of the steps. Considering that our muscles have few fast trigger fibers a frequency of about 5 steps per second, 300 steps per minute, is an upper limit for the capacity of leg muscles to contract and extend.
Cheetahs, ostriches, horses and even dogs and cats have all the leg muscles bundled way of their legs and connected to the lower point of action by long tendons. This way the lower part of their legs is very light (since it is free of muscles) and therefore can provide a much higher frequency.
Their short muscles being closer to the point of rotation of the hip and don’t have to move so much as a long leg muscles. Therefore, the power needed to swing a large muscle free very light leg is a lot less than the power needed to swing the massive
muscular human leg. This is the first reason why most mammals are faster than humans.
We also have a rather short foot. The foot gives extra leverage that allows us to use the power of the calve muscles. When we walk as opposed to running, calve muscles are used less. The foot acts as a gear, and the shorter, and the lighter the gear there will be higher the force. But it lowers the speed. The human foot allows the calve muscle to exert a lot of force on the toes. However, there will be less speed.
How fast can the fastest human run
A longer food will provide less power but greater speed like a taller gear. If you look at runner animals like cheetah, horses or simply your domestic dogs and cats, they all walk on their toes. Their feet are very long as well, even as long as the other leg bones. We humans are like motor vehicle with a gearbox stuck in the second gear while runner animals benefit from a tall gear for fast running.
So, if we can swing our legs at a frequency of about five steps per second and each step can be 2.5 meters long. This means that the top speed of a human cannot exceed 12.5 meters per second which is equal to 45 km/h no matter how strong our legs are.
How fast is the average human able to run?
These numbers may apply to Usain Bolt. But for an average human the maximum speed will be more like 30 km/h. The new research shows that, if we manage time that applies force to the ground while sprinting, our limbs and muscles can go faster and theoretically we can run 64 km/h at the max. The 64 km/h is fast but not as much as fast running animals. A fit human cannot outrun a bear, horse or a large dog. But we theoretically can outrun all of them on the long distance. It’s often believed that humans are weak and fragile animals that manage to get through the hardship of the fight for survival by virtue of their large brains.
This is not the whole story! It’s not much appreciated that humans given certain conditions can outrun any land mammal on the long distance, even cheetahs, horses and any other animal! We might not be the fastest but we are the best marathon runners on the planet.
Things that helps Human Can Run Faster
You might be asking how that is possible! Well, that’s because of the three extraordinary evolutionary traits of humans.
- We have the most efficient water cooling system in the animal world.
- We are the only animal with a two gear shifter
- We are among the very few land animals to have rear wheels, the hind legs!
Cooling System of Human Body
Let’s see the first reason water cooling! Muscles like all engines produce heat. This is because the chemical energy they received from the blood cannot be entirely converted in mechanical energy, but only a fraction of it. The rest becomes heat. And heat is good for us. We are homoeothermic hot blooded species and our body temperature must be comprised within a very narrow range to allow us to live
Too much heat, if not sufficiently dissipated, will raise the body temperature and put of a very survival at risk. The muscles of a mammal have an efficiency of 18% to 26%. This means that 18 to 26 percent of the energy that comes from the blood is converted in mechanical energy and the remaining 74 to 82 percent is either not drawn from the blood or is converted into heat.
That’s a lot of heat if you think about it, and it’s very difficult to dissipate adequately. Mainly, heat is dissipated through the skin, and the surface of the skin is just too much. As a body grows bigger its volume increases with the cubic power of its linear dimensions which are length and height. Its outer surface increases only with the square power.
If you double the length of an animal all the rest remaining equal, its body volume will increase 8 times, its skin surface will increase 4 times. So, a big animal will soon meet a deficit of a body surface through which to dissipate the heat produced by its muscles.
The evolutionary solutions to these problems are multiple. For example, elephants have developed large ears with a dense network of blood vessels that act as radiators to dissipate heat. Other animals placed a limit to the amount of heat they produce by reducing muscle metabolism, when they need to produce long-duration efforts. Some of the other animals have just started sweating.
So, how does sweating help dissipate heat? Water requires a lot of heat to evaporate. It requires almost 2300 Joules or 550 calories per each of liquid water to turn into vapor. Water does not have to be taken to its boiling point to evaporate. In essence, it can evaporate at any temperature if energy is given to it in different ways. For example by a current of air that flows by its surface. Now, imagine having your skin constantly wet and the current of air generated by running makes this layer of water evaporate. Continued sweating replaces the water that evaporates. Every gram of water that evaporates will remove two 2300 joules of heat from your skin. Your skin blood vessels will transfer heat from the blood to the skin and from there to the water.
An athlete can produce as many as 3-Liters of sweat per hour. This corresponds to 3,000 grams. If this amount of water evaporates, athlete will require nearly 7 million joules of energy. If this is done in one hour, it’s equal to almost 2 KW of cooling power.
So, we humans have the cooling system that can reach nearly 2 KW of thermal power. It removes much of the heat produced by our muscles and allows us to keep of a body temperature stable. Even under a continuous and intense muscular effort!
Assuming a cooling efficiency of 100% which is never reached, we could ideally generate a continuous muscular power of 0.6 to 0.9 horsepower. So, this is why we have no fur. The fur would insulate the layer of the sweat that lies on the skin, prevent the air current from making it evaporate. Horses also sweat, but they have fur and therefore, it is very difficult to evaporate water compared to the bare skin of a human. The heat transmission is far worse across a thick layer of liquid water trapped in the fur. As anyone who has been sweating through a flannel shirt as experienced.
Humans have the most efficient water cooling system in the animal world. But they are unique among all animals. For instance, humans can easily switch from Plantigrade deambulation to Digitigrade deambulation. When we walk, we placed entire foot on the ground and we exploit the leverage offered by the length of the foot only to lift the weight of the leg a short distance. We almost do not use our calve muscles to walk. Why? Because, less muscle mass is used and less energy is consumed, therefore less heat is produced. Walking is a slow, but extremely energy efficient way to move. Cats, dogs, horses and all other running animals always move on their toe tips, no matter how slow they want to go. They cannot put their cuff muscles at rest and their slow walking pace is not as efficient as it could be.
Bones Structure of Human for Running
When we want to run, however, we just shift to a higher gear. We do not put the whole sole of our feet on the ground anymore. But, we run on our toes. We mostly use so to speak tuitions of the feet behind the toes with the toes acting as balancers. This way the calf muscles can generate strong force acting on the leverage provided by the length of the foot to lift the entire weight of the body. Therefore, we can sufficiently use many more muscles, when running than when walking. So, we have two gears: A light one for energy efficient slow walking, and a tall one for strong fast running or climbing.
Although our species adapted to running, it never became the fast runner. Because a long foot necessary to allow fast running would have become rather awkward and useless when walking in the first gear.
We humans became the ultra-marathon runners of the animal kingdom. No other animal is able to run for 8-hours (60 km/h) in a hot climate. A horse can run much faster than a man. But after one hour even last in a warm climate, they have to stop and cool off or they will die from a heart stroke. In a cold environment the problem of body heating is not so relevant sled dogs can run for 200 kilometers at sub-zero temperatures. Also horses travel longer and faster in the cold. But humans are unbeatable for their endurance in a hot climate.
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