Running to Think

This might sound hard but I'm finding it extremely useful and fun.
In order to spend some hours at the gym I had to decrease the mileage per week. My highest priority has been about improving the core muscles that usually kick in after the 40th km.
No strength in the muscles after 4 hours of running usually means that it's pretty much over. You heard that, my friends. Over. Finito. Go home.
I am not talking about glycogen and lack of carbs. These things remain the same for every ultra marathon and the strategies to replenish the overused resources are those that almost every ultra runner already knows.

Hi my measuring freaks,
if there is anyone who does not like to measure her or his own progress, please raise your hand. Thing is that you get a boost when you have the feeling to be close to your target. And that, my friends, can happen only if you can measure it.

The easiest  and most well know method is measuring your weight with a scale. The cheap ones that you find in supermarkets are in my opinion not very accurate. Once you get a decent one there is a way to define your ideal weight by measuring your height and use the formula for BMI (body mass index) = weight / height². A healthy BMI should be in the range 18-25 but of course this number should be taken with care because it doesn't take into account body composition. Namely, a fat person can have the same BMI than a body builder.

Below you can find a BMI chart, provided you would like to know if you are in the green zone:

Table 1: BMI chart

More accurate scales for medical usage such as those that you can find in pharmacies like wellnescentra and fitnesscentra can do a great job. One brand I suggest is Tanita.
It uses BIA (Bioelectrical Impedance Analysis) technology, which sends a safe, low-level electrical signal from footplate and hand electrodes through the body. BIA is quickly calculated and it is also non-invasive. This is considered one of the most reliable ways to measure body composition, even clinically comparable to DEXA (dual-energy x-ray absorptiometry) and hydrostatic (underwater) weighing. These methods usually return your weight, fat percentage, fat mass, fat free mass, total body water, muscle mass, bone mass to provide a very complete profile of your body. 

Those scales are also quite expensive, one more reason to keep reading.
If you can have access to one of those scales in your city or gym, fine. Otherwise you can use other cheaper techniques which go under the term of kinathropometry.

Kinanthropometry is an emerging scientific specialization concerned with the application of measurement to appraise human size, shape, proportion, composition, maturation and gross function. It is a basic discipline for problem-solving in matters related to growth, exercise, performance and of course nutrition.


The measuring tools you need are:
1) a scale
2) a calibre (to measure skinfolds)
3) a measuring tape

Figure 2: Calibre

Figure 3: Skinfolds to measure

You got all, now what? What should you measure, where, how and what formula should you use?

Let's get busy.

Biometry

They are a lot of things you can measure such as height, weight, the circumference of the upper arm, waist, hip, calf, thigh and some other stuff but those are not really important. The skinfolds can be measured with a calibre.
In Figure 3 you can see the correct places that you should measure. Measure each twice or more to make sure you did it well, then take the average of those measurements.

Body Density (BD)

The measures at hand will allow you to calculate your fat percentage. There are 3 different formulae to do that. I will explain the two ones that I consider as the most accurate. These formulae adapt quite well according to your age, gender and the amount of skinfolds you measured.

1) Jackson- Pollock (3 site skinfold formula)

2) Durnin - Womersley (age 20-29)

Fat Percentage