Friday, February 26, 2010

Vertical Ascent Rate

While we just looked at an example of how walking speed changes with change in trail steepness, it is also interesting to look at how vertical ascent rate (VAR) changes with trail steepness.

Of course, I think most people would generally hypothesize that VAR increases as the grade increases, since a larger % of energy will be spent on vertical movement. I would also hypothesize that above some grade (perhaps 60-70%), VAR would begin to decrease - I am thinking about loss of friction, change in terrain, and change in biomechanical efficiency - but that is simply conjecture at this point.

We will look at only one exemplar hike (Big Iron again) which is suitable because of the breadth of gradients encountered and I was attempting to hike at a constant pace. Below is a plot of VAR vs grade % (this time I multiplied by 100% so it makes more sense, like 15% grade on a treadmill).

Wednesday, February 24, 2010

How is Hiking Speed Affected by Steepness? A GPS Graphical Analysis

The short answer is we slow down as the trail gets steeper. Yes, I know, pretty obvious.

But how much? And what steepness / speeds are hiking a 10% grade fire road fast the same exertion as hiking up a 30 % grade mountain at 2 mph?

This is one of many things interesting to look at through the experimental data that a GPS device can collect. Take a look at the graph below, which shows my hiking speed versus the steepness of the trail while on a hike up Iron Mountain in the San Gabriels.

Sunday, February 21, 2010

Energy Systems Part 2 - Aerobic Exercise

We previously went over some basics of anaerobic exercise, now on to the aerobic portion.

3. Glycolysis - Aerobic
The burning of glycogen using oxygen can last much longer than without...but how long? Well, it's going to be directly related to how much glycogen you have stored in your muscles. So when you workout, you need to eat carbohydrates to replenish these storages. If you don't, you will feel fatigued, as your body can't produce energy at the rate you are used to. That's why you'll see people eating all sorts of sugary stuff when doing multi-hour endurance activities. Gatorade came to signficance partly due to showing that by giving carbohydrate calories to people during exercise, the participants could perform the exercise for longer.

Thursday, February 18, 2010

Energy Systems Part 1 - Anaerobic Exercise

We will start backwards. When we hike (or run) we move our limbs in desired motions and speeds. To get the desired movements, we need our muscles to contract. Muscles cannot contract without having energy available. So we need to get energy to the muscles.

Where does the energy come from, you say? Well, it depends on the energy demands of the muscle. Compare walking at 3 mph on a flat terrain to walking 3pmh on a steep trail and running 6 mph on a steep trail. Wouldn't you agree the energy demands are different? In the 6 mph case, there is a high energy demand and it is probable that this pace could not be kept up for long. High energy demand exercise is considered anaerobic exercise. This basically means that the energy for the muscles is produced without using oxygen, and that the energy supply is quite limited - only lasting for a few minutes. But because the energy can be created without oxygen, a lot of it can be produced quickly, so fast movements that last up to 3 minutes will rely on this source.

If you try to run up a 25% grade, you'll be quickly using up your anaerobic energy

Thursday, February 11, 2010

Google Earth Topo Overlay - A Mapping Discussion

One of the 10 essentials is a map (and a GPS is nice too), especially if you are going into a new area, or even better (worse) going off maintained trails to do some fun exploration.

When this happens, often times available maps (i.e. USGS topo, Tom Harrison maps) are not sufficient because the trail / area you planning on using isn't there.

So some people like to use mapping software like National Geographic TOPO! or Garmin Mapsource to make maps and wapoints to print out and download to a GPS.

Well now I think there's a better, if not somewhat more tedious option.

Thursday, February 4, 2010

Hyperventilation - Does it do any good?

There has been some disagreement that hyperventilating helps absorb more oxygen into the blood when at high altitudes.

Does it?


Here's why

Wednesday, February 3, 2010

Understanding Altitude Sickness

I originally posted this on the socalhikes blog but this is a more appropriate home for it.

Background: You want to hike Mt. Whitney (~ 14,500 ft), the tallest peak in the contiguous United States. Or you may want to ascend other high peaks in the Sierras, or elsewhere.

Perception: This is the hardest hike you will do, therefore you need to train for it. I have heard this many times.

Reality: The hike certainly is a biggie (~ 22 - 24 miles, 6500 ft gain), but there are many other hikes that have more stringent cardiovascular conditioning demands. In fact, the main trail up to Mt. Whitney is not very steep.

What makes Mt. Whitney difficult is the altitude and the low pressure of oxygen.

Problem: Cardiovascular training does not improve a person's ability to handle low altitude, so how else can we adapt?