[personal dev] Fun with Crossfit

I tried the Crossfit bodyweight exercises from here today:

http://zenhabits.net/2008/08/minimalist-fitness-how-to-get-in-lean-shape-with-little-or-no-equipment/

It's clear my body has not optimized at all for this kind of exercise.  I was able to do 10-20 repetitions of each exercise in order but it was brutal.  (A couple of the ones on the list were easy, but I hit a wall on most of them after 10-20 repetitions)  I was surprised at how poorly I did on some of the leg-focused exercises given that I do a lot of running and dancing based exercise. 

However, it makes sense.  The body is incredibly adaptable.  Muscles will optimize for strength or endurance depending on how you're using them.  My body is essentially a DDR-playing machine at this point... my legs are great with endurance and lots of quick movements, but not strength. 

This stuff definitely fits the time-efficiency criterion.  I went from zero to incredibly tired in 5 minutes.


More discussion of the body's adaptability (from this site):  It's amazing stuff. 

"Go heavy or go home" is a common saying among bodybuilders. But, while it's crucial that you use a weight that provides a challenging load, the mantra is flawed. That's because muscle fibers can grow in two ways. The first is when the myofibrils -- the parts of the fiber that contain the contracting proteins -- increase in number and density. This type of growth leads to strength gains and can be accomplished by using heavy weights that allow only one to seven repetitions.

The second type of growth, however, occurs when your muscles are forced to contract for longer periods of time. Typically, this means using lighter loads that allow you to complete 12 to 15 repetitions. This increases the number of energy-producing structures within the fiber. So you don't get significantly stronger, but you do get bigger.

Using a repetition range that falls between the two causes a combination of both types of growth, but each to a lesser degree. And that's why Cosgrove uses all three repetition ranges. For instance, he might prescribe five repetitions of each exercise on Monday, 15 on Wednesday, and 10 on Friday. "It not only leads to better growth but also helps keep you from hitting plateaus," he says.

And indeed, in a 2002 study, Arizona State University researchers discovered that men who alternated their repetition ranges in each of three weekly training sessions gained twice as much strength as men who didn't vary their repetitions. To Cosgrove, it's just another case of a logical approach generating a logical result.

Unusual linkages in biology -- unhealthy gums cause heart disease.

It turns out that having unhealthy, inflamed gums dramatically increases the risk of heart disease.    Study here.

From a programmer's perspective, the body is an enormous hack.  All the components are deeply interdependent, causing weird and unusual bugs and linkages.  Given that the body was programmed by a genetic algorithm and not a skilled intelligent designer, it's not surprising.  There's probably mild selection pressure for more cleanly programmed organisms, but the common programming technique of building a better and cleaner "version 2.0" program from scratch is simply not available to evolution!

Here's how the linkage works:

Unhealthy gums have constant bacterial infections, which cause inflammation as well as an easy path for foreign bacteria to enter the bloodstream.  The constant inflammation puts stress on the body, since it's constantly fighting an infection.  This stress leads to the release of hormones that cause heart disease. 

Inerestingly, the vast majority of gum disease is caused by a single species of bacterium that eats sugar and secretes tooth-dissolving lactic acid.   Some enterprising genetic engineers have designed another bacterium that can live in our mouth and secrete a chemical that kills these bacteria.  I'm a little wary of their solution, but it serves as an example of the wide variety of creative solutions that genetic engineering affords us.