It is not the intent of this site to provide medical advice. This blog chronicles my fitness and nutrition philosophy based on some combination of my experience, research, and biases. You read, and you decide.

Wednesday, April 14, 2010

Barefoot Training

There's a growing subculture of athletes, mostly long-distance runners, who are starting to turn away from fancy training footwear. "Born to Run" by Christopher McDougall is probably the most popular piece of literature on the subject.

I'm totally on board. From an evolutionary standpoint, it makes no sense to strap a 2-inch rubber heel to your perfectly functional foot. Barefoot runners tend to land on the forefoot, in a position that allows the calf muscle to get involved and absorb the stress of impact. Athletes with elevated, cushioned heels tend to land on their heels. In this case, the muscles of the lower leg and ankle are not involved in minimizing the impact force on joints.

Take a look at these two comparative videos. I feel this is pretty strong evidence supporting the idea that wearing elevated-heel shoes inhibits us from achieving our natural motion:

Forefoot striking vs. Heel Striking

Note that both runners are barefoot, even though runners who have learned to run barefoot generally tend to strike with the forefoot. Heel-striking with a cushioned sole looks like this.

I'm aware of one study that analyzed the torque experienced by different joints in shoe-clad and barefoot runners. This study found reduced torque in the hips, knees, and ankles of the barefoot group. Unfortunately, only the abstract seems to be available for free.

Since our culture demands footwear for most occasions, I'd recommend a couple of options:

-Vibram 5fingers
These are my personal choice. I work, train, and walk around in these. The toes are separated, and the sole is super thin. I've had one pair for over 6 months, and they are still in fantastic shape. I think part of this has to do with the fact that I walk more carefully when I wear these. At just shy of 200 lbs, I find myself accidentally sneaking up on people occasionally because my feet contact the ground fairly softly. They feel good, but it's still not the same as being barefoot.

I should mention, however, that these shoes are terrible in the mud and really start to stink after a while. They are washing machine-friendly, though.

-Terra Plana VivoBarefoot These look great, but I haven't given them a try yet. The Vibrams are quite a fashion statement, and the TPVB's offer a more subtle alternative (at a much higher price).

I'm not affiliated with either of these companies. There might be some other good alternatives out there as well of which I am unaware.

Finally, a word of caution: As with a lot of the subjects I discuss, there is a definite transition period from the cultural norm (wearing elevated heels) to the functional (barefoot). Your calf muscles and Achilles tendon need a little time to build up and adjust to their larger role of cushioning initial impact. If you're going to try barefoot training, start with shorter distances and durations.

Extra reading:
Running Before the Modern Shoe

Saturday, April 3, 2010

Ketosis: A Primer

We are interested in being healthy, lean, strong, energetic and athletic. To this end, we want a metabolic scenario in which we have access to the largest stores of energy in the body: triglycerides (stored form of fat). Many of us have more than we need. This has everything to do with hormone balance, which has everything to do with diet and exercise.

Let’s stick with diet for now. If you eat few enough carbohydrates, your body will not be getting enough sugar from your diet to keep blood glucose levels in the desired range. Lucky for us, the body has other mechanisms that can be called upon to maintain serum glucose levels. The backbone of stored fat molecules (triglycerides) can be converted to glucose in limited quantities, but the main source is a process called gluconeogenesis which takes place in the liver. This process involves the conversion of amino acids to glucose. In victims of starvation, these amino acids come from muscle tissue. In low-carbers, these amino acids come from the diet as long as there is adequate protein intake.

So, today I didn’t eat enough carbohydrates to maintain my blood sugar levels without other mechanisms kicking in. As a rule of thumb, this will be the case if you eat fewer than 120-130 carbs per day. Gluconeogenesis ramps up and converts amino acids into glucose in the liver. This process requires energy from fat. Gluconeogensis uses part of the fat, and the leftovers are converted into water-soluble fat molecules called ketone bodies. Ketone bodies act as an energy substitute for a chunk of our glucose needs (not all). So, now fat is being burned as part of the process that keeps our blood-sugar normalized.

Now, you’ll run into plenty of people who will tell you ketosis is dangerous. Usually this is because:

-Almost everyone in our culture eats a surplus of carbohydrates, meaning their bodies are exclusively metabolizing glucose for their main source of energy. Ketosis is seen as an abnormal state, often associated only with starvation.

-There is an adjustment period for the transition from glucose metabolism to ketone metabolism (note: you’re never completely off glucose metabolism; ketones act as a supplement). Short term studies tend to show a substantial decrease in performance in endurance tests. This effect disappears in longer term studies, as explained here.

-Diabetics can go into ketosis even when their blood sugar levels are high, which is not good. My understanding is that since they are insulin-resistant/deficient, the glucose in the blood stream is not being taken in by the cells for energy. A person with normal hormonal control should not experience this. Ketosis is not ketoacidosis. The body eliminates excess ketone bodies through the urine and breath to maintain blood pH levels. This is why you can test for ketosis with urine strips.

-I’ve heard the claim that ketosis causes bad breath. My experience with friends who test positive for ketosis contradicts this. I’ve never noticed bad breath on them, nor have I been told my breath is bad.

Dr. Eades explains these processes in a little more depth (and with a little more expertise) here and here.

Friday, April 2, 2010

Body Weight (Mostly) Circuit

I'm a fan of minimalist fitness. Some of the standard gym equipment is very useful, but a lot of the new props out there are pretty goofy and useless in my opinion. If you're aiming for general fitness and overall health, then your workout needs to reflect that. Running on a treadmill and watching tv is not a functional workout. Running barefoot intervals on a trail is a lot closer. I'll develop this theme in far more depth in future posts.

Anyways, the weather was absolutely beautiful today, so I took the opportunity to do a body weight (mostly) circuit in a park. I like this routine because you can take it just about anywhere, especially if you substitute hill sprints for the last station that requires 30 lb dumbbells.

It also happens to be a pretty full workout using mostly bodyweight. Ability to manage bodyweight is definitely a measure of functional fitness in my mind.

Props: Tree branch or pull-up bar, 2 x 30 lb dumbbells, 2 strips of cloth

Circuit style, meaning no scheduled rest:

15 frog hops
6 one handed push-ups each side
30 pull-ups (Kipping acceptable)
15 clap-ups
4 pistol squats with each leg
10 handstand push-ups
200 yard (estimated) sprint carrying a 30 lb dumbbell in each hand. Since I study jiu-jitsu, I was interested in further developing grip strength, so we looped a small towel around each dumbbell handle and gripped the towel instead of the actual handle.

We didn't time it, but rest assured that I had to take a couple breathers during this routine.