Posts tagged ‘fitness’

Survival of the Fittest is Not Related to Physical Fitness

Almost everyone has heard of evolution and most of us have a vague idea of what it means. Animals with useful traits survive and pass on their genes. Over time, these positive traits become more common and a species evolves. Most of us aren’t scientists, though, and a number of evolution myths have popped up over time.

Myth #1: Evolution is “just” a theory

We usually think of theories as being possibilities, not facts. A “theory” in science, though, takes on a different meaning. I personally like this definition from the National Academy of Sciences:

“a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses”

In other words, a scientific theory is an explanation that has been backed up by many studies and a substantial amount of evidence. We don’t call it a “fact” because science can always change as we learn new information. We’re all pretty sure the Earth rotates around the Sun yet that concept is called the heliocentric theory. It’s pretty unlikely we’ll find any evidence that goes against this “theory” but scientists still don’t call it a fact.

Evolution

Myth #2: Humans evolved from monkeys

This is a common one and often used in an attempt to discredit evolutionary theories. It’s also not true; humans did not evolve from monkeys. We did share an ancestor with African apes (note that “apes” aren’t monkeys) about 8 million years ago but that doesn’t mean we evolved from them. Instead, there was a great ancestor that eventually gave rise to humans and apes. We’re most closely related to chimpanzees because of this ancestor but there were two distinct evolutionary paths.

When the human species began to evolve, the chimpanzee species was evolving separately. We’re related, we didn’t directly evolve from any modern primate species. We do share over 90% of our DNA with non-human primates, including gorillas and other great apes. On the other hand, humans also share 90% of their DNA with mice! That doesn’t mean humans evolved from mice, it’s just a result of most mammals sharing genes.

Myth #3: Survival of the fittest means the strongest will survive

Sometimes people will use the term “survival of the fittest” to excuse a behavior. I’ve unfortunately overheard someone say that we shouldn’t help those weaker than us because “it’s survival of the fittest!” The average person interprets this idea, originally thought up by Charles Darwin, as meaning that the very strongest will survive. The problem is that “fitness” has an entirely different meaning in biology. It doesn’t refer to strength, health, or physical fitness at all. Instead, biological “fitness” refers to the ability to pass on your genes, generally by having offspring.

In evolution, the end goal is to pass on your genes to the next generation. That doesn’t necessarily require being the strongest, however. In fact, animals that get into too many fights might become injured or killed. Even if they won most of those fights and were the strongest in their group, death means they won’t be passing on their genes. Those animals would therefore be considered to have low fitness. On the other hand, a somewhat weaker animal that stays out of danger might be able to successfully raise several offspring. That animal would be said to have high fitness. In primates, including humans, being a good parent will often raise fitness more than being strong. From an evolutionary standpoint, being able to lift heavy weights means nothing if you never settle down and raise children.

If you want to learn more about how evolution works, the University of California in Berkeley (among others) have put together great evolution resources: click here.

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Sources: Science and Creationism, National Human Genome Research Institute, Smithsonian, Natural History

Photo: Wellcome Images UK

July 17, 2016 at 12:18 pm Leave a comment

How to Buy the Right Shoes for Your Feet

Considering how much time you spend wearing shoes, how much time have you spent understanding what’s unique about your feet?

Unless you’re an avid runner or maybe work at a shoe store, you probably don’t know how to buy shoes that compliment your feet and the way you use them. It can be hard enough to find a shoe that looks good, fits on your foot and feels comfortable, but it takes even more to find a pair that fits your arch and the angle of your ankles. But there is a way.

Even if you don’t run, you can still benefit from buying the right running (or walking) shoes — especially if you spend a lot of time on your feet at work or at play.

For example, the only “running” I do is running errands, but I often wear running shoes because they’re comfortable and lightweight. With the right shoes, there is less stress on your feet, ankles, knees and hips.

When you walk, the heel of your foot will touch the ground first and as you roll your foot forward, your weight will be transferred to the front of your foot. Depending on the angle of your foot, you may be putting more weight on the inside or outside of your foot. Doing that hundreds or thousands of times a day can lead to pain and discomfort in your feet and other parts of your body.

If your hips, knees or ankles produce external rotation, you will be more likely to angle your feet as you walk (known as pronation of the foot). Your shoes can compensate for natural irregularities or make them worse and that’s why it’s important to get the right shoes.

Good shoe stores will help determine your arch type and level of pronation. Once you know your arch type and pronation, there are different shoes that will suit you. A local running shop is a good place to start, they’re generally the most knowledgeable retailers of shoes. Some websites with good fitting advice are: Road Runner Sports, Zappos, Dick’s and New Balance.

One way to determine your arch type is by standing (to put weight on your feet), then sliding your index finger under your arch. If you get your finger up to 1/2 an inch under your foot then you’ve got a low arch. 1/2 inch to 1 inch is a medium arch. More than an inch is a high arch.

The other way to determine arch type is the paper bag test. You wet your feet and stand on a paper bag. Looking at your wet footprint and the size of the gap left by your arch, you can tell if you have a low, medium or high arch. This way is pretty common, but it’s a bit more subjective than the index finger method.

To determine your pronation (ankle roll), you’ll need the help of a friend. They will stand behind you to see how your ankles behave as you walk. If your ankles stay very straight, then you have neutral pronation. If they roll slightly inward or outward then you’re considered an under-pronator. If they roll inward excessively, then you’re an over-pronator.

Another way to determine pronation is to put a used pair of your running shoes on a flat surface and see if the shoes tilt inward towards each other, or tilt outward, away from each other.

Shoes are divided into three categories for different feet type: stability, motion control and neutral. Stability shoes are for under-pronators. Motion control shoes are for severe over-pronators and perhaps obviously, neutral shoes are for neutral pronation.

Most online retailers categorize shoes into these groups. A good shoe store will be able to tell you which shoes are your type as well.

The other approach to running footwear is: barefoot. There is a popular book on running called Born to Run which suggests that we are literally born to run in our bare feet and the best runners in the world come from tribes of barefoot runners who run well into old age without injury.

For now, I think I’ll stick with my runners.

Thanks to Kristen for suggesting this secret!

Broken Secrets | By: Chad Upton

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Sources: Wikipedia (Foot type), New Balance (Running Gait), Zappos, Dick’s

Photo: Jason Alley (cc)

June 7, 2010 at 5:00 am 2 comments


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